diff --git a/accessible/base/TextAttrs.cpp b/accessible/base/TextAttrs.cpp
index eced0a21710c..6acc803029d2 100644
--- a/accessible/base/TextAttrs.cpp
+++ b/accessible/base/TextAttrs.cpp
@@ -460,8 +460,8 @@ bool
 TextAttrsMgr::FontFamilyTextAttr::
   GetFontFamily(nsIFrame* aFrame, nsString& aFamily)
 {
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(aFrame, getter_AddRefs(fm), 1.0f);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(aFrame, 1.0f);
 
   gfxFontGroup* fontGroup = fm->GetThebesFontGroup();
   gfxFont* font = fontGroup->GetFirstValidFont();
@@ -618,8 +618,8 @@ TextAttrsMgr::FontWeightTextAttr::
 {
   // nsFont::width isn't suitable here because it's necessary to expose real
   // value of font weight (used font might not have some font weight values).
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(aFrame, getter_AddRefs(fm), 1.0f);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(aFrame, 1.0f);
 
   gfxFontGroup *fontGroup = fm->GetThebesFontGroup();
   gfxFont *font = fontGroup->GetFirstValidFont();
diff --git a/accessible/windows/sdn/sdnTextAccessible.cpp b/accessible/windows/sdn/sdnTextAccessible.cpp
index fa7b4c507e0b..b51caf44ed8c 100644
--- a/accessible/windows/sdn/sdnTextAccessible.cpp
+++ b/accessible/windows/sdn/sdnTextAccessible.cpp
@@ -179,8 +179,8 @@ sdnTextAccessible::get_fontFamily(BSTR __RPC_FAR* aFontFamily)
   if (!frame)
     return E_FAIL;
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(frame, getter_AddRefs(fm), 1.0f);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(frame, 1.0f);
 
   const nsString& name =
     fm->GetThebesFontGroup()->GetFirstValidFont()->GetName();
diff --git a/dom/canvas/CanvasRenderingContext2D.cpp b/dom/canvas/CanvasRenderingContext2D.cpp
index 25668c11f714..ea01005194c5 100644
--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -2468,13 +2468,12 @@ public:
 
   virtual float GetExLength() const override
   {
-    RefPtr<nsFontMetrics> fontMetrics;
     nsDeviceContext* dc = mPresContext->DeviceContext();
     nsFontMetrics::Params params;
     params.language = mFontLanguage;
     params.explicitLanguage = mExplicitLanguage;
     params.textPerf = mPresContext->GetTextPerfMetrics();
-    dc->GetMetricsFor(mFont, params, *getter_AddRefs(fontMetrics));
+    RefPtr<nsFontMetrics> fontMetrics = dc->GetMetricsFor(mFont, params);
     return NSAppUnitsToFloatPixels(fontMetrics->XHeight(),
                                    nsPresContext::AppUnitsPerCSSPixel());
   }
@@ -3236,9 +3235,8 @@ CanvasRenderingContext2D::SetFontInternal(const nsAString& aFont,
   params.explicitLanguage = fontStyle->mExplicitLanguage;
   params.userFontSet = c->GetUserFontSet();
   params.textPerf = c->GetTextPerfMetrics();
-  RefPtr<nsFontMetrics> metrics;
-  c->DeviceContext()->GetMetricsFor(resizedFont, params,
-                                    *getter_AddRefs(metrics));
+  RefPtr<nsFontMetrics> metrics =
+    c->DeviceContext()->GetMetricsFor(resizedFont, params);
 
   gfxFontGroup* newFontGroup = metrics->GetThebesFontGroup();
   CurrentState().fontGroup = newFontGroup;
diff --git a/dom/events/ContentEventHandler.cpp b/dom/events/ContentEventHandler.cpp
index 8101d5afcded..ea734423b263 100644
--- a/dom/events/ContentEventHandler.cpp
+++ b/dom/events/ContentEventHandler.cpp
@@ -1453,22 +1453,14 @@ ContentEventHandler::OnQueryCaretRect(WidgetQueryContentEvent* aEvent)
   rect.x = posInFrame.x;
   rect.y = posInFrame.y;
 
-  nscoord fontHeight = 0;
-  RefPtr<nsFontMetrics> fontMetrics;
-  rv = nsLayoutUtils::
-    GetInflatedFontMetricsForFrame(frame, getter_AddRefs(fontMetrics));
-  if (NS_WARN_IF(!fontMetrics)) {
-    // If we cannot get font height, use frame size instead.
-    fontHeight = isVertical ? frame->GetSize().width : frame->GetSize().height;
-  } else {
-    fontHeight = fontMetrics->MaxAscent() + fontMetrics->MaxDescent();
-  }
+  RefPtr<nsFontMetrics> fontMetrics =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(frame);
   if (isVertical) {
-    rect.width = fontHeight;
+    rect.width = fontMetrics->MaxHeight();
     rect.height = caretRect.height;
   } else {
     rect.width = caretRect.width;
-    rect.height = fontHeight;
+    rect.height = fontMetrics->MaxHeight();
   }
 
   rv = ConvertToRootRelativeOffset(frame, rect);
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 705c6bb63a55..a041de871088 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -2513,8 +2513,8 @@ EventStateManager::GetScrollAmount(nsPresContext* aPresContext,
   if (!rootFrame) {
     return nsSize(0, 0);
   }
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(rootFrame, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(rootFrame);
   NS_ENSURE_TRUE(fm, nsSize(0, 0));
   return nsSize(fm->AveCharWidth(), fm->MaxHeight());
 }
diff --git a/dom/svg/SVGContentUtils.cpp b/dom/svg/SVGContentUtils.cpp
index 9bbd56b8a6fe..6b0f8f9760e8 100644
--- a/dom/svg/SVGContentUtils.cpp
+++ b/dom/svg/SVGContentUtils.cpp
@@ -340,9 +340,8 @@ SVGContentUtils::GetFontXHeight(nsStyleContext *aStyleContext)
   nsPresContext *presContext = aStyleContext->PresContext();
   MOZ_ASSERT(presContext, "NULL pres context in GetFontXHeight");
 
-  RefPtr<nsFontMetrics> fontMetrics;
-  nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext,
-                                               getter_AddRefs(fontMetrics));
+  RefPtr<nsFontMetrics> fontMetrics =
+    nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext);
 
   if (!fontMetrics) {
     // ReportToConsole
diff --git a/gfx/src/nsDeviceContext.cpp b/gfx/src/nsDeviceContext.cpp
index 8e9bfd846d9a..ffc2c59dde39 100644
--- a/gfx/src/nsDeviceContext.cpp
+++ b/gfx/src/nsDeviceContext.cpp
@@ -64,9 +64,8 @@ public:
     void Init(nsDeviceContext* aContext);
     void Destroy();
 
-    nsresult GetMetricsFor(const nsFont& aFont,
-                           const nsFontMetrics::Params& aParams,
-                           nsFontMetrics*& aMetrics);
+    already_AddRefed<nsFontMetrics> GetMetricsFor(
+        const nsFont& aFont, const nsFontMetrics::Params& aParams);
 
     void FontMetricsDeleted(const nsFontMetrics* aFontMetrics);
     void Compact();
@@ -122,10 +121,9 @@ nsFontCache::Observe(nsISupports*, const char* aTopic, const char16_t*)
     return NS_OK;
 }
 
-nsresult
+already_AddRefed<nsFontMetrics>
 nsFontCache::GetMetricsFor(const nsFont& aFont,
-                           const nsFontMetrics::Params& aParams,
-                           nsFontMetrics*& aMetrics)
+                           const nsFontMetrics::Params& aParams)
 {
     nsIAtom* language = aParams.language ? aParams.language
                                          : mLocaleLanguage.get();
@@ -133,10 +131,9 @@ nsFontCache::GetMetricsFor(const nsFont& aFont,
     // First check our cache
     // start from the end, which is where we put the most-recent-used element
 
-    nsFontMetrics* fm;
     int32_t n = mFontMetrics.Length() - 1;
     for (int32_t i = n; i >= 0; --i) {
-        fm = mFontMetrics[i];
+        nsFontMetrics* fm = mFontMetrics[i];
         if (fm->Font().Equals(aFont) &&
             fm->GetUserFontSet() == aParams.userFontSet &&
             fm->Language() == language &&
@@ -147,8 +144,7 @@ nsFontCache::GetMetricsFor(const nsFont& aFont,
                 mFontMetrics.AppendElement(fm);
             }
             fm->GetThebesFontGroup()->UpdateUserFonts();
-            NS_ADDREF(aMetrics = fm);
-            return NS_OK;
+            return do_AddRef(Move(fm));
         }
     }
 
@@ -156,14 +152,11 @@ nsFontCache::GetMetricsFor(const nsFont& aFont,
 
     nsFontMetrics::Params params = aParams;
     params.language = language;
-    fm = new nsFontMetrics(aFont, params, mContext);
-    NS_ADDREF(fm);
+    RefPtr<nsFontMetrics> fm = new nsFontMetrics(aFont, params, mContext);
     // the mFontMetrics list has the "head" at the end, because append
     // is cheaper than insert
-    mFontMetrics.AppendElement(fm);
-    aMetrics = fm;
-    NS_ADDREF(aMetrics);
-    return NS_OK;
+    mFontMetrics.AppendElement(do_AddRef(fm.get()).take());
+    return fm.forget();
 }
 
 void
@@ -227,10 +220,9 @@ nsDeviceContext::~nsDeviceContext()
     }
 }
 
-nsresult
+already_AddRefed<nsFontMetrics>
 nsDeviceContext::GetMetricsFor(const nsFont& aFont,
-                               const nsFontMetrics::Params& aParams,
-                               nsFontMetrics*& aMetrics)
+                               const nsFontMetrics::Params& aParams)
 {
     if (!mFontCache) {
         mFontCache = new nsFontCache();
@@ -238,7 +230,7 @@ nsDeviceContext::GetMetricsFor(const nsFont& aFont,
         mFontCache->Init(this);
     }
 
-    return mFontCache->GetMetricsFor(aFont, aParams, aMetrics);
+    return mFontCache->GetMetricsFor(aFont, aParams);
 }
 
 nsresult
diff --git a/gfx/src/nsDeviceContext.h b/gfx/src/nsDeviceContext.h
index 40377324b4a1..92665c7cf592 100644
--- a/gfx/src/nsDeviceContext.h
+++ b/gfx/src/nsDeviceContext.h
@@ -113,12 +113,9 @@ public:
      * Get the nsFontMetrics that describe the properties of
      * an nsFont.
      * @param aFont font description to obtain metrics for
-     * @param aMetrics out parameter for font metrics
-     * @return error status
      */
-    nsresult GetMetricsFor(const nsFont& aFont,
-                           const nsFontMetrics::Params& aParams,
-                           nsFontMetrics*& aMetrics);
+    already_AddRefed<nsFontMetrics> GetMetricsFor(
+        const nsFont& aFont, const nsFontMetrics::Params& aParams);
 
     /**
      * Notification when a font metrics instance created for this device is
diff --git a/layout/base/PositionedEventTargeting.cpp b/layout/base/PositionedEventTargeting.cpp
index 6f1675ffd207..3e6a2cdd0bfd 100644
--- a/layout/base/PositionedEventTargeting.cpp
+++ b/layout/base/PositionedEventTargeting.cpp
@@ -525,8 +525,8 @@ IsElementClickableAndReadable(nsIFrame* aFrame, WidgetGUIEvent* aEvent, const Ev
   }
 
   if (testFontSize) {
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame, getter_AddRefs(fm));
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
     if (fm && fm->EmHeight() > 0 && // See bug 1171731
         (pc->AppUnitsToGfxUnits(fm->EmHeight()) * cumulativeResolution) < limitReadableSize) {
       return false;
diff --git a/layout/base/nsCaret.cpp b/layout/base/nsCaret.cpp
index e6fc8bca0832..fdad06680b69 100644
--- a/layout/base/nsCaret.cpp
+++ b/layout/base/nsCaret.cpp
@@ -321,8 +321,8 @@ nsCaret::GetGeometryForFrame(nsIFrame* aFrame,
                "We should not be in the middle of reflow");
   nscoord baseline = frame->GetCaretBaseline();
   nscoord ascent = 0, descent = 0;
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
   NS_ASSERTION(fm, "We should be able to get the font metrics");
   if (fm) {
     ascent = fm->MaxAscent();
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index 5c8dea78f6ea..124e921c640a 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -4024,19 +4024,14 @@ nsLayoutUtils::ComputeObjectDestRect(const nsRect& aConstraintRect,
   return nsRect(imageTopLeftPt, concreteObjectSize);
 }
 
-nsresult
-nsLayoutUtils::GetFontMetricsForFrame(const nsIFrame* aFrame,
-                                      nsFontMetrics** aFontMetrics,
-                                      float aInflation)
+already_AddRefed<nsFontMetrics>
+nsLayoutUtils::GetFontMetricsForFrame(const nsIFrame* aFrame, float aInflation)
 {
-  return nsLayoutUtils::GetFontMetricsForStyleContext(aFrame->StyleContext(),
-                                                      aFontMetrics,
-                                                      aInflation);
+  return GetFontMetricsForStyleContext(aFrame->StyleContext(), aInflation);
 }
 
-nsresult
+already_AddRefed<nsFontMetrics>
 nsLayoutUtils::GetFontMetricsForStyleContext(nsStyleContext* aStyleContext,
-                                             nsFontMetrics** aFontMetrics,
                                              float aInflation)
 {
   nsPresContext* pc = aStyleContext->PresContext();
@@ -4059,13 +4054,12 @@ nsLayoutUtils::GetFontMetricsForStyleContext(nsStyleContext* aStyleContext,
   // which would be lossy.  Fortunately, in such cases, aInflation is
   // guaranteed to be 1.0f.
   if (aInflation == 1.0f) {
-    return pc->DeviceContext()->GetMetricsFor(styleFont->mFont, params,
-                                              *aFontMetrics);
+    return pc->DeviceContext()->GetMetricsFor(styleFont->mFont, params);
   }
 
   nsFont font = styleFont->mFont;
   font.size = NSToCoordRound(font.size * aInflation);
-  return pc->DeviceContext()->GetMetricsFor(font, params, *aFontMetrics);
+  return pc->DeviceContext()->GetMetricsFor(font, params);
 }
 
 nsIFrame*
@@ -8492,8 +8486,8 @@ nsLayoutUtils::SetBSizeFromFontMetrics(const nsIFrame* aFrame,
                                        WritingMode aLineWM,
                                        WritingMode aFrameWM)
 {
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
 
   if (fm) {
     // Compute final height of the frame.
diff --git a/layout/base/nsLayoutUtils.h b/layout/base/nsLayoutUtils.h
index 2884b4cd1c0f..217853ef95fb 100644
--- a/layout/base/nsLayoutUtils.h
+++ b/layout/base/nsLayoutUtils.h
@@ -1222,47 +1222,36 @@ public:
   /**
    * Get the font metrics corresponding to the frame's style data.
    * @param aFrame the frame
-   * @param aFontMetrics the font metrics result
    * @param aSizeInflation number to multiply font size by
-   * @return success or failure code
    */
-  static nsresult GetFontMetricsForFrame(const nsIFrame* aFrame,
-                                         nsFontMetrics** aFontMetrics,
-                                         float aSizeInflation);
+  static already_AddRefed<nsFontMetrics> GetFontMetricsForFrame(
+    const nsIFrame* aFrame, float aSizeInflation);
 
-  static nsresult GetInflatedFontMetricsForFrame(const nsIFrame* aFrame,
-                                                 nsFontMetrics** aFontMetrics)
+  static already_AddRefed<nsFontMetrics>
+    GetInflatedFontMetricsForFrame(const nsIFrame* aFrame)
   {
-    return GetFontMetricsForFrame(aFrame, aFontMetrics,
-                                  FontSizeInflationFor(aFrame));
+    return GetFontMetricsForFrame(aFrame, FontSizeInflationFor(aFrame));
   }
 
   /**
    * Get the font metrics corresponding to the given style data.
    * @param aStyleContext the style data
-   * @param aFontMetrics the font metrics result
    * @param aSizeInflation number to multiply font size by
-   * @return success or failure code
    */
-  static nsresult GetFontMetricsForStyleContext(nsStyleContext* aStyleContext,
-                                                nsFontMetrics** aFontMetrics,
-                                                float aSizeInflation = 1.0f);
+  static already_AddRefed<nsFontMetrics> GetFontMetricsForStyleContext(
+      nsStyleContext* aStyleContext, float aSizeInflation = 1.0f);
 
   /**
    * Get the font metrics of emphasis marks corresponding to the given
    * style data. The result is same as GetFontMetricsForStyleContext
    * except that the font size is scaled down to 50%.
    * @param aStyleContext the style data
-   * @param aFontMetrics the font metrics result
    * @param aInflation number to multiple font size by
-   * @return success or failure code
    */
-  static nsresult GetFontMetricsOfEmphasisMarks(nsStyleContext* aStyleContext,
-                                                nsFontMetrics** aFontMetrics,
-                                                float aInflation)
+  static already_AddRefed<nsFontMetrics> GetFontMetricsOfEmphasisMarks(
+      nsStyleContext* aStyleContext, float aInflation)
   {
-    return GetFontMetricsForStyleContext(aStyleContext, aFontMetrics,
-                                         aInflation * 0.5f);
+    return GetFontMetricsForStyleContext(aStyleContext, aInflation * 0.5f);
   }
 
   /**
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 6c183438d872..4ecf2cc6fe3d 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -10344,9 +10344,8 @@ void ReflowCountMgr::PaintCount(const char*     aName,
       nsFontMetrics::Params params;
       params.language = nsGkAtoms::x_western;
       params.textPerf = aPresContext->GetTextPerfMetrics();
-      RefPtr<nsFontMetrics> fm;
-      aPresContext->DeviceContext()->
-        GetMetricsFor(font, params, *getter_AddRefs(fm));
+      RefPtr<nsFontMetrics> fm =
+        aPresContext->DeviceContext()->GetMetricsFor(font, params);
 
       char buf[16];
       int len = snprintf_literal(buf, "%d", counter->mCount);
diff --git a/layout/forms/nsListControlFrame.cpp b/layout/forms/nsListControlFrame.cpp
index 570bf9e032f4..c595ce462387 100644
--- a/layout/forms/nsListControlFrame.cpp
+++ b/layout/forms/nsListControlFrame.cpp
@@ -1551,16 +1551,9 @@ nsListControlFrame::IsLeftButton(nsIDOMEvent* aMouseEvent)
 nscoord
 nsListControlFrame::CalcFallbackRowBSize(float aFontSizeInflation)
 {
-  nscoord rowBSize = 0;
-
-  RefPtr<nsFontMetrics> fontMet;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet),
-                                        aFontSizeInflation);
-  if (fontMet) {
-    rowBSize = fontMet->MaxHeight();
-  }
-
-  return rowBSize;
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForFrame(this, aFontSizeInflation);
+  return fontMet->MaxHeight();
 }
 
 nscoord
diff --git a/layout/forms/nsMeterFrame.cpp b/layout/forms/nsMeterFrame.cpp
index f97c279fd1cf..16ecf18e3b71 100644
--- a/layout/forms/nsMeterFrame.cpp
+++ b/layout/forms/nsMeterFrame.cpp
@@ -230,10 +230,8 @@ nsMeterFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
                               const LogicalSize& aPadding,
                               bool aShrinkWrap)
 {
-  RefPtr<nsFontMetrics> fontMet;
-  NS_ENSURE_SUCCESS(nsLayoutUtils::GetFontMetricsForFrame(this,
-                                                          getter_AddRefs(fontMet), 1.0f),
-                    LogicalSize(aWM));
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
 
   const WritingMode wm = GetWritingMode();
   LogicalSize autoSize(wm);
@@ -251,9 +249,8 @@ nsMeterFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
 nscoord
 nsMeterFrame::GetMinISize(nsRenderingContext *aRenderingContext)
 {
-  RefPtr<nsFontMetrics> fontMet;
-  NS_ENSURE_SUCCESS(
-      nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet), 1.0f), 0);
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
 
   nscoord minISize = fontMet->Font().size; // 1em
 
diff --git a/layout/forms/nsProgressFrame.cpp b/layout/forms/nsProgressFrame.cpp
index b88f24f9a969..0ecb1d250ab9 100644
--- a/layout/forms/nsProgressFrame.cpp
+++ b/layout/forms/nsProgressFrame.cpp
@@ -257,9 +257,8 @@ nsProgressFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
 nscoord
 nsProgressFrame::GetMinISize(nsRenderingContext *aRenderingContext)
 {
-  RefPtr<nsFontMetrics> fontMet;
-  NS_ENSURE_SUCCESS(
-      nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet), 1.0f), 0);
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
 
   nscoord minISize = fontMet->Font().size; // 1em
 
diff --git a/layout/forms/nsTextControlFrame.cpp b/layout/forms/nsTextControlFrame.cpp
index ac522bfb37ad..49d4ff7e20c5 100644
--- a/layout/forms/nsTextControlFrame.cpp
+++ b/layout/forms/nsTextControlFrame.cpp
@@ -155,11 +155,8 @@ nsTextControlFrame::CalcIntrinsicSize(nsRenderingContext* aRenderingContext,
   nscoord charWidth   = 0;
   nscoord charMaxAdvance  = 0;
 
-  RefPtr<nsFontMetrics> fontMet;
-  nsresult rv =
-    nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet),
-                                          aFontSizeInflation);
-  NS_ENSURE_SUCCESS(rv, rv);
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForFrame(this, aFontSizeInflation);
 
   lineHeight =
     nsHTMLReflowState::CalcLineHeight(GetContent(), StyleContext(),
@@ -523,9 +520,8 @@ nsTextControlFrame::Reflow(nsPresContext*   aPresContext,
     lineHeight = nsHTMLReflowState::CalcLineHeight(GetContent(), StyleContext(),
                                                    NS_AUTOHEIGHT, inflation);
   }
-  RefPtr<nsFontMetrics> fontMet;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet),
-                                        inflation);
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForFrame(this, inflation);
   // now adjust for our borders and padding
   aDesiredSize.SetBlockStartAscent(
     nsLayoutUtils::GetCenteredFontBaseline(fontMet, lineHeight,
diff --git a/layout/generic/MathMLTextRunFactory.cpp b/layout/generic/MathMLTextRunFactory.cpp
index ea7a28a97d12..1034d39572da 100644
--- a/layout/generic/MathMLTextRunFactory.cpp
+++ b/layout/generic/MathMLTextRunFactory.cpp
@@ -746,11 +746,9 @@ MathMLTextRunFactory::RebuildTextRun(nsTransformedTextRun* aTextRun,
     params.explicitLanguage = styles[0]->mExplicitLanguage;
     params.userFontSet = pc->GetUserFontSet();
     params.textPerf = pc->GetTextPerfMetrics();
-    RefPtr<nsFontMetrics> metrics;
-    pc->DeviceContext()->GetMetricsFor(font, params, *getter_AddRefs(metrics));
-    if (metrics) {
-      newFontGroup = metrics->GetThebesFontGroup();
-    }
+    RefPtr<nsFontMetrics> metrics =
+      pc->DeviceContext()->GetMetricsFor(font, params);
+    newFontGroup = metrics->GetThebesFontGroup();
   }
 
   if (!newFontGroup) {
diff --git a/layout/generic/TextOverflow.cpp b/layout/generic/TextOverflow.cpp
index 9b20e6658ed8..a40929f54aaf 100644
--- a/layout/generic/TextOverflow.cpp
+++ b/layout/generic/TextOverflow.cpp
@@ -49,8 +49,8 @@ private:
 static gfxTextRun*
 GetEllipsisTextRun(nsIFrame* aFrame)
 {
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
   LazyReferenceRenderingDrawTargetGetterFromFrame lazyRefDrawTargetGetter(aFrame);
   return fm->GetThebesFontGroup()->GetEllipsisTextRun(
     aFrame->PresContext()->AppUnitsPerDevPixel(),
@@ -255,8 +255,8 @@ nsDisplayTextOverflowMarker::PaintTextToContext(nsRenderingContext* aCtx,
                     gfxTextRun::DrawParams(aCtx->ThebesContext()));
     }
   } else {
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetInflatedFontMetricsForFrame(mFrame, getter_AddRefs(fm));
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(mFrame);
     nsLayoutUtils::DrawString(mFrame, *fm, aCtx, mStyle->mString.get(),
                               mStyle->mString.Length(), pt);
   }
@@ -808,8 +808,8 @@ TextOverflow::Marker::SetupString(nsIFrame* aFrame)
   } else {
     nsRenderingContext rc(
       aFrame->PresContext()->PresShell()->CreateReferenceRenderingContext());
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame, getter_AddRefs(fm));
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
     mISize = nsLayoutUtils::AppUnitWidthOfStringBidi(mStyle->mString, aFrame,
                                                      *fm, rc);
   }
diff --git a/layout/generic/nsBRFrame.cpp b/layout/generic/nsBRFrame.cpp
index da0d9e911417..2d7ec6487e1d 100644
--- a/layout/generic/nsBRFrame.cpp
+++ b/layout/generic/nsBRFrame.cpp
@@ -121,8 +121,8 @@ BRFrame::Reflow(nsPresContext* aPresContext,
       // We also do this in strict mode because BR should act like a
       // normal inline frame.  That line-height is used is important
       // here for cases where the line-height is less than 1.
-      RefPtr<nsFontMetrics> fm;
-      nsLayoutUtils::GetInflatedFontMetricsForFrame(this, getter_AddRefs(fm));
+      RefPtr<nsFontMetrics> fm =
+        nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
       if (fm) {
         nscoord logicalHeight = aReflowState.CalcLineHeight();
         finalSize.BSize(wm) = logicalHeight;
diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 79021bb1fcf1..942cd8ddccfe 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -505,9 +505,9 @@ nsBlockFrame::GetCaretBaseline() const
       return bp.top + firstLine->mFirstChild->GetCaretBaseline();
     }
   }
-  RefPtr<nsFontMetrics> fm;
   float inflation = nsLayoutUtils::FontSizeInflationFor(this);
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm), inflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, inflation);
   nscoord lineHeight =
     nsHTMLReflowState::CalcLineHeight(GetContent(), StyleContext(),
                                       contentRect.height, inflation);
@@ -2625,8 +2625,8 @@ nsBlockFrame::ReflowDirtyLines(nsBlockReflowState& aState)
         }
       }
 
-      RefPtr<nsFontMetrics> fm;
-      nsLayoutUtils::GetInflatedFontMetricsForFrame(this, getter_AddRefs(fm));
+      RefPtr<nsFontMetrics> fm =
+        nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
 
       nscoord minAscent =
         nsLayoutUtils::GetCenteredFontBaseline(fm, aState.mMinLineHeight,
diff --git a/layout/generic/nsBulletFrame.cpp b/layout/generic/nsBulletFrame.cpp
index cb402b20f519..a2fafbb1c540 100644
--- a/layout/generic/nsBulletFrame.cpp
+++ b/layout/generic/nsBulletFrame.cpp
@@ -304,7 +304,6 @@ nsBulletFrame::PaintBullet(nsRenderingContext& aRenderingContext, nsPoint aPt,
     }
   }
 
-  RefPtr<nsFontMetrics> fm;
   ColorPattern color(ToDeviceColor(
                        nsLayoutUtils::GetColor(this, eCSSProperty_color)));
 
@@ -412,8 +411,8 @@ nsBulletFrame::PaintBullet(nsRenderingContext& aRenderingContext, nsPoint aPt,
       aRenderingContext.ThebesContext()->SetColor(
         Color::FromABGR(nsLayoutUtils::GetColor(this, eCSSProperty_color)));
 
-      nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                            GetFontSizeInflation());
+      RefPtr<nsFontMetrics> fm =
+        nsLayoutUtils::GetFontMetricsForFrame(this, GetFontSizeInflation());
       nsAutoString text;
       GetListItemText(text);
       WritingMode wm = GetWritingMode();
@@ -535,9 +534,8 @@ nsBulletFrame::GetDesiredSize(nsPresContext*  aCX,
 
   const nsStyleList* myList = StyleList();
   nscoord ascent;
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        aFontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, aFontSizeInflation);
 
   RemoveStateBits(BULLET_FRAME_IMAGE_LOADING);
 
@@ -892,9 +890,8 @@ nsBulletFrame::GetLogicalBaseline(WritingMode aWritingMode) const
   if (GetStateBits() & BULLET_FRAME_IMAGE_LOADING) {
     ascent = BSize(aWritingMode);
   } else {
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                          GetFontSizeInflation());
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForFrame(this, GetFontSizeInflation());
     CounterStyle* listStyleType = StyleList()->GetCounterStyle();
     switch (listStyleType->GetStyle()) {
       case NS_STYLE_LIST_STYLE_NONE:
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 4dd66c4f74c7..cee4fd9419b2 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -3904,8 +3904,8 @@ ScrollFrameHelper::ScrollSnap(const nsPoint &aDestination,
 nsSize
 ScrollFrameHelper::GetLineScrollAmount() const
 {
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(mOuter, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(mOuter);
   NS_ASSERTION(fm, "FontMetrics is null, assuming fontHeight == 1 appunit");
   static nscoord sMinLineScrollAmountInPixels = -1;
   if (sMinLineScrollAmountInPixels < 0) {
diff --git a/layout/generic/nsHTMLReflowState.cpp b/layout/generic/nsHTMLReflowState.cpp
index 77219ba220e7..49a5c3f7046a 100644
--- a/layout/generic/nsHTMLReflowState.cpp
+++ b/layout/generic/nsHTMLReflowState.cpp
@@ -2693,10 +2693,8 @@ ComputeLineHeight(nsStyleContext* aStyleContext,
     }
   }
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext,
-                                               getter_AddRefs(fm),
-                                               aFontSizeInflation);
+  RefPtr<nsFontMetrics> fm = nsLayoutUtils::
+    GetFontMetricsForStyleContext(aStyleContext, aFontSizeInflation);
   return GetNormalLineHeight(fm);
 }
 
diff --git a/layout/generic/nsImageFrame.cpp b/layout/generic/nsImageFrame.cpp
index 8c88e0af8e96..d05a7ff9ce2d 100644
--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -1130,8 +1130,8 @@ nsImageFrame::DisplayAltText(nsPresContext*      aPresContext,
   // Set font and color
   aRenderingContext.ThebesContext()->
     SetColor(Color::FromABGR(StyleColor()->mColor));
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(this, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
 
   // Format the text to display within the formatting rect
 
diff --git a/layout/generic/nsLineLayout.cpp b/layout/generic/nsLineLayout.cpp
index a60a38159a16..d09824d4d93e 100644
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -1680,9 +1680,8 @@ nsLineLayout::PlaceTopBottomFrames(PerSpanData* psd,
 static nscoord
 GetBSizeOfEmphasisMarks(nsIFrame* aSpanFrame, float aInflation)
 {
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsOfEmphasisMarks(
-    aSpanFrame->StyleContext(), getter_AddRefs(fm), aInflation);
+  RefPtr<nsFontMetrics> fm = nsLayoutUtils::
+    GetFontMetricsOfEmphasisMarks(aSpanFrame->StyleContext(), aInflation);
   return fm->MaxHeight();
 }
 
@@ -1774,11 +1773,10 @@ nsLineLayout::VerticalAlignFrames(PerSpanData* psd)
   nsIFrame* spanFrame = spanFramePFD->mFrame;
 
   // Get the parent frame's font for all of the frames in this span
-  RefPtr<nsFontMetrics> fm;
   float inflation =
     GetInflationForBlockDirAlignment(spanFrame, mInflationMinFontSize);
-  nsLayoutUtils::GetFontMetricsForFrame(spanFrame, getter_AddRefs(fm),
-                                        inflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(spanFrame, inflation);
 
   bool preMode = mStyleText->WhiteSpaceIsSignificant();
 
diff --git a/layout/generic/nsPageFrame.cpp b/layout/generic/nsPageFrame.cpp
index 16bf48986a2b..60b3fc64c7ed 100644
--- a/layout/generic/nsPageFrame.cpp
+++ b/layout/generic/nsPageFrame.cpp
@@ -633,9 +633,8 @@ nsPageFrame::PaintHeaderFooter(nsRenderingContext& aRenderingContext,
   nsFontMetrics::Params params;
   params.userFontSet = pc->GetUserFontSet();
   params.textPerf = pc->GetTextPerfMetrics();
-  RefPtr<nsFontMetrics> fontMet;
-  pc->DeviceContext()->GetMetricsFor(mPD->mHeadFootFont, params,
-                                     *getter_AddRefs(fontMet));
+  RefPtr<nsFontMetrics> fontMet =
+    pc->DeviceContext()->GetMetricsFor(mPD->mHeadFootFont, params);
 
   nscoord ascent = 0;
   nscoord visibleHeight = 0;
diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index ccdbd1631aa5..6a5c36a2ae7a 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -1814,12 +1814,8 @@ GetFontGroupForFrame(nsIFrame* aFrame, float aFontSizeInflation,
   if (aOutFontMetrics)
     *aOutFontMetrics = nullptr;
 
-  RefPtr<nsFontMetrics> metrics;
-  nsLayoutUtils::GetFontMetricsForFrame(aFrame, getter_AddRefs(metrics),
-                                        aFontSizeInflation);
-
-  if (!metrics)
-    return nullptr;
+  RefPtr<nsFontMetrics> metrics =
+    nsLayoutUtils::GetFontMetricsForFrame(aFrame, aFontSizeInflation);
 
   if (aOutFontMetrics) {
     *aOutFontMetrics = metrics;
@@ -5168,9 +5164,8 @@ nsTextFrame::UpdateTextEmphasis(WritingMode aWM, PropertyProvider& aProvider)
     return nsRect();
   }
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsOfEmphasisMarks(
-    StyleContext(), getter_AddRefs(fm), GetFontSizeInflation());
+  RefPtr<nsFontMetrics> fm = nsLayoutUtils::
+    GetFontMetricsOfEmphasisMarks(StyleContext(), GetFontSizeInflation());
   EmphasisMarkInfo* info = new EmphasisMarkInfo;
   info->textRun =
     GenerateTextRunForEmphasisMarks(this, fm, aWM, styleText);
@@ -6946,9 +6941,8 @@ nsTextFrame::CombineSelectionUnderlineRect(nsPresContext* aPresContext,
 
   nsRect givenRect = aRect;
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        GetFontSizeInflation());
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, GetFontSizeInflation());
   gfxFontGroup* fontGroup = fm->GetThebesFontGroup();
   gfxFont* firstFont = fontGroup->GetFirstValidFont();
   WritingMode wm = GetWritingMode();
diff --git a/layout/mathml/nsMathMLChar.cpp b/layout/mathml/nsMathMLChar.cpp
index 341edd1886ac..a902ba50d863 100644
--- a/layout/mathml/nsMathMLChar.cpp
+++ b/layout/mathml/nsMathMLChar.cpp
@@ -996,9 +996,8 @@ nsMathMLChar::SetFontFamily(nsPresContext*          aPresContext,
     params.explicitLanguage = styleFont->mExplicitLanguage;
     params.userFontSet = aPresContext->GetUserFontSet();
     params.textPerf = aPresContext->GetTextPerfMetrics();
-    RefPtr<nsFontMetrics> fm;
-    aPresContext->DeviceContext()->
-      GetMetricsFor(font, params, *getter_AddRefs(fm));
+    RefPtr<nsFontMetrics> fm =
+      aPresContext->DeviceContext()->GetMetricsFor(font, params);
     // Set the font if it is an unicode table
     // or if the same family name has been found
     gfxFont *firstFont = fm->GetThebesFontGroup()->GetFirstValidFont();
@@ -1537,9 +1536,8 @@ nsMathMLChar::StretchInternal(nsPresContext*           aPresContext,
   params.explicitLanguage = styleFont->mExplicitLanguage;
   params.userFontSet = aPresContext->GetUserFontSet();
   params.textPerf = aPresContext->GetTextPerfMetrics();
-  RefPtr<nsFontMetrics> fm;
-  aPresContext->DeviceContext()->
-    GetMetricsFor(font, params, *getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    aPresContext->DeviceContext()->GetMetricsFor(font, params);
   uint32_t len = uint32_t(mData.Length());
   nsAutoPtr<gfxTextRun> textRun;
   textRun = fm->GetThebesFontGroup()->
diff --git a/layout/mathml/nsMathMLContainerFrame.cpp b/layout/mathml/nsMathMLContainerFrame.cpp
index faf2c9f5c339..f0dae173dd8f 100644
--- a/layout/mathml/nsMathMLContainerFrame.cpp
+++ b/layout/mathml/nsMathMLContainerFrame.cpp
@@ -49,8 +49,8 @@ nsMathMLContainerFrame::ReflowError(DrawTarget* aDrawTarget,
 
   ///////////////
   // Set font
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(this, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
 
   // bounding metrics
   nsAutoString errorMsg; errorMsg.AssignLiteral("invalid-markup");
@@ -92,8 +92,8 @@ void nsDisplayMathMLError::Paint(nsDisplayListBuilder* aBuilder,
                                  nsRenderingContext* aCtx)
 {
   // Set color and font ...
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(mFrame, getter_AddRefs(fm), 1.0f);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(mFrame, 1.0f);
 
   nsPoint pt = ToReferenceFrame();
   int32_t appUnitsPerDevPixel = mFrame->PresContext()->AppUnitsPerDevPixel();
diff --git a/layout/mathml/nsMathMLFrame.cpp b/layout/mathml/nsMathMLFrame.cpp
index a8363979b91a..42c7c89b427b 100644
--- a/layout/mathml/nsMathMLFrame.cpp
+++ b/layout/mathml/nsMathMLFrame.cpp
@@ -232,10 +232,8 @@ nsMathMLFrame::CalcLength(nsPresContext*   aPresContext,
   }
   else if (eCSSUnit_XHeight == unit) {
     aPresContext->SetUsesExChUnits(true);
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext,
-                                                 getter_AddRefs(fm),
-                                                 aFontSizeInflation);
+    RefPtr<nsFontMetrics> fm = nsLayoutUtils::
+      GetFontMetricsForStyleContext(aStyleContext, aFontSizeInflation);
     nscoord xHeight = fm->XHeight();
     return NSToCoordRound(aCSSValue.GetFloatValue() * (float)xHeight);
   }
diff --git a/layout/mathml/nsMathMLFrame.h b/layout/mathml/nsMathMLFrame.h
index 287de00ce04c..0e6464d1a6df 100644
--- a/layout/mathml/nsMathMLFrame.h
+++ b/layout/mathml/nsMathMLFrame.h
@@ -198,9 +198,8 @@ public:
                       nscoord&        aSubDrop,
                       float           aFontSizeInflation) 
   {
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetFontMetricsForFrame(aChild, getter_AddRefs(fm),
-                                          aFontSizeInflation);
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForFrame(aChild, aFontSizeInflation);
     GetSubDrop(fm, aSubDrop);
   }
 
@@ -209,9 +208,8 @@ public:
                       nscoord&        aSupDrop,
                       float           aFontSizeInflation) 
   {
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetFontMetricsForFrame(aChild, getter_AddRefs(fm),
-                                          aFontSizeInflation);
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForFrame(aChild, aFontSizeInflation);
     GetSupDrop(fm, aSupDrop);
   }
 
diff --git a/layout/mathml/nsMathMLTokenFrame.cpp b/layout/mathml/nsMathMLTokenFrame.cpp
index 21a78b2e775e..604aeaa62e7b 100644
--- a/layout/mathml/nsMathMLTokenFrame.cpp
+++ b/layout/mathml/nsMathMLTokenFrame.cpp
@@ -173,8 +173,8 @@ nsMathMLTokenFrame::Place(DrawTarget*          aDrawTarget,
     mBoundingMetrics += childSize.mBoundingMetrics;
   }
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetInflatedFontMetricsForFrame(this, getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
   nscoord ascent = fm->MaxAscent();
   nscoord descent = fm->MaxDescent();
 
diff --git a/layout/mathml/nsMathMLmencloseFrame.cpp b/layout/mathml/nsMathMLmencloseFrame.cpp
index 9dc02df765f2..93176793a657 100644
--- a/layout/mathml/nsMathMLmencloseFrame.cpp
+++ b/layout/mathml/nsMathMLmencloseFrame.cpp
@@ -344,9 +344,8 @@ nsMathMLmencloseFrame::PlaceInternal(DrawTarget*          aDrawTarget,
   nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
 
   float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
   GetRuleThickness(aDrawTarget, fm, mRuleThickness);
   if (mRuleThickness < onePixel) {
     mRuleThickness = onePixel;
diff --git a/layout/mathml/nsMathMLmfencedFrame.cpp b/layout/mathml/nsMathMLmfencedFrame.cpp
index 915e3a05a315..db58d51709f7 100644
--- a/layout/mathml/nsMathMLmfencedFrame.cpp
+++ b/layout/mathml/nsMathMLmfencedFrame.cpp
@@ -223,9 +223,8 @@ nsMathMLmfencedFrame::Reflow(nsPresContext*          aPresContext,
   int32_t i;
   const nsStyleFont* font = StyleFont();
   float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
   nscoord axisHeight, em;
   GetAxisHeight(aReflowState.rendContext->GetDrawTarget(), fm, axisHeight);
   GetEmHeight(fm, em);
@@ -612,9 +611,8 @@ nsMathMLmfencedFrame::GetIntrinsicISizeMetrics(nsRenderingContext* aRenderingCon
   nsPresContext* presContext = PresContext();
   const nsStyleFont* font = StyleFont();
   float fontSizeInflation = nsLayoutUtils:: FontSizeInflationFor(this);
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
   nscoord em;
   GetEmHeight(fm, em);
 
diff --git a/layout/mathml/nsMathMLmfracFrame.cpp b/layout/mathml/nsMathMLmfracFrame.cpp
index b5b88d074559..4cc04283d2dc 100644
--- a/layout/mathml/nsMathMLmfracFrame.cpp
+++ b/layout/mathml/nsMathMLmfracFrame.cpp
@@ -218,9 +218,8 @@ nsMathMLmfracFrame::PlaceInternal(DrawTarget*          aDrawTarget,
   nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
 
   float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
 
   nscoord defaultRuleThickness, axisHeight;
   nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
diff --git a/layout/mathml/nsMathMLmmultiscriptsFrame.cpp b/layout/mathml/nsMathMLmmultiscriptsFrame.cpp
index 01a3599fe388..99807b905b1c 100644
--- a/layout/mathml/nsMathMLmmultiscriptsFrame.cpp
+++ b/layout/mathml/nsMathMLmmultiscriptsFrame.cpp
@@ -185,9 +185,8 @@ nsMathMLmmultiscriptsFrame::PlaceMultiScript(nsPresContext*  aPresContext,
 
   // get x-height (an ex)
   const nsStyleFont* font = aFrame->StyleFont();
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(baseFrame, getter_AddRefs(fm),
-                                        aFontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(baseFrame, aFontSizeInflation);
 
   nscoord xHeight = fm->XHeight();
 
diff --git a/layout/mathml/nsMathMLmoFrame.cpp b/layout/mathml/nsMathMLmoFrame.cpp
index 145d9c800c29..12e876100e12 100644
--- a/layout/mathml/nsMathMLmoFrame.cpp
+++ b/layout/mathml/nsMathMLmoFrame.cpp
@@ -362,9 +362,8 @@ nsMathMLmoFrame::ProcessOperatorData()
       // Cache the default values of lspace and rspace.
       // since these values are relative to the 'em' unit, convert to twips now
       nscoord em;
-      RefPtr<nsFontMetrics> fm;
-      nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                            fontSizeInflation);
+      RefPtr<nsFontMetrics> fm =
+        nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
       GetEmHeight(fm, em);
 
       mEmbellishData.leadingSpace = NSToCoordRound(lspace * em);
@@ -619,9 +618,8 @@ nsMathMLmoFrame::Stretch(DrawTarget*          aDrawTarget,
 
   // get the axis height;
   float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
   nscoord axisHeight, height;
   GetAxisHeight(aDrawTarget, fm, axisHeight);
 
diff --git a/layout/mathml/nsMathMLmrootFrame.cpp b/layout/mathml/nsMathMLmrootFrame.cpp
index c667d11d20fd..2045180fe01f 100644
--- a/layout/mathml/nsMathMLmrootFrame.cpp
+++ b/layout/mathml/nsMathMLmrootFrame.cpp
@@ -225,10 +225,9 @@ nsMathMLmrootFrame::Reflow(nsPresContext*          aPresContext,
   ////////////
   // Prepare the radical symbol and the overline bar
 
-  RefPtr<nsFontMetrics> fm;
   float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
 
   nscoord ruleThickness, leading, psi;
   GetRadicalParameters(fm, StyleFont()->mMathDisplay ==
@@ -382,9 +381,8 @@ nsMathMLmrootFrame::GetIntrinsicISizeMetrics(nsRenderingContext* aRenderingConte
                                           fontSizeInflation);
 
   nscoord dxSqr;
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
   GetRadicalXOffsets(indexWidth, sqrWidth, fm, nullptr, &dxSqr);
 
   nscoord width = dxSqr + sqrWidth + baseWidth;
diff --git a/layout/mathml/nsMathMLmtableFrame.cpp b/layout/mathml/nsMathMLmtableFrame.cpp
index 2583fb414a58..951757ee0b0e 100644
--- a/layout/mathml/nsMathMLmtableFrame.cpp
+++ b/layout/mathml/nsMathMLmtableFrame.cpp
@@ -506,9 +506,8 @@ ParseSpacingAttribute(nsMathMLmtableFrame* aFrame, nsIAtom* aAttribute)
   nscoord value2;
   // Set defaults
   float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(aFrame);
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(aFrame, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(aFrame, fontSizeInflation);
   if (nsGkAtoms::rowspacing_ == aAttribute) {
     value = kDefaultRowspacingEx * fm->XHeight();
     value2 = 0;
@@ -882,8 +881,8 @@ nsMathMLmtableOuterFrame::Reflow(nsPresContext*          aPresContext,
     case eAlign_axis:
     default: {
       // XXX should instead use style data from the row of reference here ?
-      RefPtr<nsFontMetrics> fm;
-      nsLayoutUtils::GetInflatedFontMetricsForFrame(this, getter_AddRefs(fm));
+      RefPtr<nsFontMetrics> fm =
+        nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
       nscoord axisHeight;
       GetAxisHeight(aReflowState.rendContext->GetDrawTarget(), fm, axisHeight);
       if (rowFrame) {
diff --git a/layout/mathml/nsMathMLmunderoverFrame.cpp b/layout/mathml/nsMathMLmunderoverFrame.cpp
index 0532849257e0..9e8aff7bc312 100644
--- a/layout/mathml/nsMathMLmunderoverFrame.cpp
+++ b/layout/mathml/nsMathMLmunderoverFrame.cpp
@@ -398,9 +398,8 @@ nsMathMLmunderoverFrame::Place(DrawTarget*          aDrawTarget,
   ////////////////////
   // Place Children
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
-                                        fontSizeInflation);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
 
   nscoord xHeight = fm->XHeight();
   nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
diff --git a/layout/style/nsFontFaceUtils.cpp b/layout/style/nsFontFaceUtils.cpp
index 376b02f23c0f..d715dfe06cf3 100644
--- a/layout/style/nsFontFaceUtils.cpp
+++ b/layout/style/nsFontFaceUtils.cpp
@@ -34,10 +34,8 @@ StyleContextContainsFont(nsStyleContext* aStyleContext,
 
   // family name is in the fontlist, check to see if the font group
   // associated with the frame includes the specific userfont
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext,
-                                               getter_AddRefs(fm),
-                                               1.0f);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext, 1.0f);
 
   if (fm->GetThebesFontGroup()->ContainsUserFont(aFont)) {
     return true;
diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index 940a50d40ae7..19573d047244 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -335,10 +335,7 @@ GetMetricsFor(nsPresContext* aPresContext,
   params.userFontSet =
     aUseUserFontSet ? aPresContext->GetUserFontSet() : nullptr;
   params.textPerf = aPresContext->GetTextPerfMetrics();
-  RefPtr<nsFontMetrics> fm;
-  aPresContext->DeviceContext()->
-    GetMetricsFor(font, params, *getter_AddRefs(fm));
-  return fm.forget();
+  return aPresContext->DeviceContext()->GetMetricsFor(font, params);
 }
 
 
diff --git a/layout/xul/nsListBoxBodyFrame.cpp b/layout/xul/nsListBoxBodyFrame.cpp
index 74400c618045..7fb7e453b0fb 100644
--- a/layout/xul/nsListBoxBodyFrame.cpp
+++ b/layout/xul/nsListBoxBodyFrame.cpp
@@ -197,8 +197,8 @@ nsListBoxBodyFrame::Init(nsIContent*       aContent,
       scrollbarFrame->SetScrollbarMediatorContent(GetContent());
     }
   }
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm), 1.0f);
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
   mRowHeight = fm->MaxHeight();
 }
 
@@ -728,9 +728,8 @@ nsListBoxBodyFrame::ComputeIntrinsicISize(nsBoxLayoutState& aBoxLayoutState)
             }
           }
 
-          RefPtr<nsFontMetrics> fm;
-          nsLayoutUtils::GetFontMetricsForStyleContext(styleContext,
-                                                       getter_AddRefs(fm));
+          RefPtr<nsFontMetrics> fm =
+            nsLayoutUtils::GetFontMetricsForStyleContext(styleContext);
 
           nscoord textWidth =
             nsLayoutUtils::AppUnitWidthOfStringBidi(value, this, *fm,
diff --git a/layout/xul/nsTextBoxFrame.cpp b/layout/xul/nsTextBoxFrame.cpp
index 54e88ae4fab5..5c55e3c11df8 100644
--- a/layout/xul/nsTextBoxFrame.cpp
+++ b/layout/xul/nsTextBoxFrame.cpp
@@ -458,8 +458,8 @@ nsTextBoxFrame::DrawText(nsRenderingContext& aRenderingContext,
     } while (0 != decorMask &&
              (f = nsLayoutUtils::GetParentOrPlaceholderFor(f)));
 
-    RefPtr<nsFontMetrics> fontMet;
-    nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet), 1.0f);
+    RefPtr<nsFontMetrics> fontMet =
+      nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
     fontMet->SetVertical(wm.IsVertical());
     fontMet->SetTextOrientation(StyleVisibility()->mTextOrientation);
 
@@ -633,8 +633,8 @@ nsTextBoxFrame::CalculateTitleForWidth(nsRenderingContext& aRenderingContext,
         return 0;
     }
 
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm), 1.0f);
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
 
     // see if the text will completely fit in the width given
     nscoord titleWidth =
@@ -969,8 +969,8 @@ nsTextBoxFrame::DoLayout(nsBoxLayoutState& aBoxLayoutState)
     nsRect scrollBounds(nsPoint(0, 0), GetSize());
     nsRect textRect = mTextDrawRect;
     
-    RefPtr<nsFontMetrics> fontMet;
-    nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet), 1.0f);
+    RefPtr<nsFontMetrics> fontMet =
+      nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
     nsBoundingMetrics metrics = 
       fontMet->GetInkBoundsForVisualOverflow(mCroppedTitle.get(),
                                              mCroppedTitle.Length(),
@@ -1030,8 +1030,8 @@ nsTextBoxFrame::GetTextSize(nsRenderingContext& aRenderingContext,
                             const nsString& aString,
                             nsSize& aSize, nscoord& aAscent)
 {
-    RefPtr<nsFontMetrics> fontMet;
-    nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet), 1.0f);
+    RefPtr<nsFontMetrics> fontMet =
+      nsLayoutUtils::GetFontMetricsForFrame(this, 1.0f);
     aSize.height = fontMet->MaxHeight();
     aSize.width =
       nsLayoutUtils::AppUnitWidthOfStringBidi(aString, this, *fontMet,
diff --git a/layout/xul/tree/nsTreeBodyFrame.cpp b/layout/xul/tree/nsTreeBodyFrame.cpp
index 8b511142a986..d86ea7983899 100644
--- a/layout/xul/tree/nsTreeBodyFrame.cpp
+++ b/layout/xul/tree/nsTreeBodyFrame.cpp
@@ -1249,9 +1249,8 @@ nsTreeBodyFrame::GetCoordsForCellItem(int32_t aRow, nsITreeColumn* aCol, const n
     // we add in borders and padding to the text dimension and give that back. 
     nsStyleContext* textContext = GetPseudoStyleContext(nsCSSAnonBoxes::moztreecelltext);
 
-    RefPtr<nsFontMetrics> fm;
-    nsLayoutUtils::GetFontMetricsForStyleContext(textContext,
-                                                 getter_AddRefs(fm));
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForStyleContext(textContext);
     nscoord height = fm->MaxHeight();
 
     nsMargin textMargin;
@@ -1621,9 +1620,8 @@ nsTreeBodyFrame::GetItemWithinCellAt(nscoord aX, const nsRect& aCellRect,
 
   AdjustForBorderPadding(textContext, textRect);
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForStyleContext(textContext,
-                                               getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForStyleContext(textContext);
   AdjustForCellText(cellText, aRowIndex, aColumn, rc, *fm, textRect);
 
   if (aX >= textRect.x && aX < textRect.x + textRect.width)
@@ -1749,9 +1747,8 @@ nsTreeBodyFrame::GetCellWidth(int32_t aRow, nsTreeColumn* aCol,
   // Get the borders and padding for the text.
   GetBorderPadding(textContext, bp);
 
-  RefPtr<nsFontMetrics> fm;
-  nsLayoutUtils::GetFontMetricsForStyleContext(textContext,
-                                               getter_AddRefs(fm));
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetFontMetricsForStyleContext(textContext);
   // Get the width of the text itself
   nscoord width = nsLayoutUtils::AppUnitWidthOfStringBidi(cellText, this, *fm,
                                                           *aRenderingContext);
@@ -3730,9 +3727,8 @@ nsTreeBodyFrame::PaintText(int32_t              aRowIndex,
   textRect.Deflate(bp);
 
   // Compute our text size.
-  RefPtr<nsFontMetrics> fontMet;
-  nsLayoutUtils::GetFontMetricsForStyleContext(textContext,
-                                               getter_AddRefs(fontMet));
+  RefPtr<nsFontMetrics> fontMet =
+    nsLayoutUtils::GetFontMetricsForStyleContext(textContext);
 
   nscoord height = fontMet->MaxHeight();
   nscoord baseline = fontMet->MaxAscent();