diff --git a/gfx/tests/gfxWordCacheTest.cpp b/gfx/tests/gfxWordCacheTest.cpp
index 70bed86c1368..16838ec7594d 100644
--- a/gfx/tests/gfxWordCacheTest.cpp
+++ b/gfx/tests/gfxWordCacheTest.cpp
@@ -15,6 +15,7 @@
 #include "gfxPlatform.h"
 
 #include "gfxFontTest.h"
+#include "mozilla/Attributes.h"
 
 #if defined(XP_MACOSX)
 #include "gfxTestCocoaHelper.h"
@@ -31,7 +32,7 @@ static FrameTextRunCache *gTextRuns = nsnull;
 /*
  * Cache textruns and expire them after 3*10 seconds of no use.
  */
-class FrameTextRunCache : public nsExpirationTracker<gfxTextRun,3> {
+class FrameTextRunCache MOZ_FINAL : public nsExpirationTracker<gfxTextRun,3> {
 public:
  enum { TIMEOUT_SECONDS = 10 };
  FrameTextRunCache()
diff --git a/layout/base/nsFrameTraversal.cpp b/layout/base/nsFrameTraversal.cpp
index a0dc0ab2260b..dc4fd4b8223b 100644
--- a/layout/base/nsFrameTraversal.cpp
+++ b/layout/base/nsFrameTraversal.cpp
@@ -17,6 +17,8 @@ public:
 
   NS_DECL_ISUPPORTS
 
+  virtual ~nsFrameIterator() {}
+
   virtual void First();
   virtual void Next();
   virtual nsIFrame* CurrentItem();
diff --git a/layout/base/nsLayoutHistoryState.cpp b/layout/base/nsLayoutHistoryState.cpp
index 31aedd928afd..9751b50851fb 100644
--- a/layout/base/nsLayoutHistoryState.cpp
+++ b/layout/base/nsLayoutHistoryState.cpp
@@ -12,9 +12,10 @@
 #include "nsWeakReference.h"
 #include "nsClassHashtable.h"
 #include "nsPresState.h"
+#include "mozilla/Attributes.h"
 
-class nsLayoutHistoryState : public nsILayoutHistoryState,
-                             public nsSupportsWeakReference
+class nsLayoutHistoryState MOZ_FINAL : public nsILayoutHistoryState,
+                                       public nsSupportsWeakReference
 {
 public:
   NS_HIDDEN_(nsresult) Init();
diff --git a/layout/base/nsPresShell.h b/layout/base/nsPresShell.h
index d42b643815a0..f6ea7f062e07 100644
--- a/layout/base/nsPresShell.h
+++ b/layout/base/nsPresShell.h
@@ -35,6 +35,7 @@
 #include "nsGUIEvent.h"
 #include "nsContentUtils.h"
 #include "nsRefreshDriver.h"
+#include "mozilla/Attributes.h"
 
 class nsRange;
 class nsIDragService;
@@ -596,7 +597,7 @@ protected:
   // Check if aEvent is a mouse event and record the mouse location for later
   // synth mouse moves.
   void RecordMouseLocation(nsGUIEvent* aEvent);
-  class nsSynthMouseMoveEvent : public nsARefreshObserver {
+  class nsSynthMouseMoveEvent MOZ_FINAL : public nsARefreshObserver {
   public:
     nsSynthMouseMoveEvent(PresShell* aPresShell, bool aFromScroll)
       : mPresShell(aPresShell), mFromScroll(aFromScroll) {
diff --git a/layout/base/nsRefreshDriver.h b/layout/base/nsRefreshDriver.h
index 1eabc0f2cf40..0ae6c88e949e 100644
--- a/layout/base/nsRefreshDriver.h
+++ b/layout/base/nsRefreshDriver.h
@@ -20,6 +20,7 @@
 #include "nsAutoPtr.h"
 #include "nsTHashtable.h"
 #include "nsHashKeys.h"
+#include "mozilla/Attributes.h"
 
 class nsPresContext;
 class nsIPresShell;
@@ -45,7 +46,7 @@ public:
   virtual void WillRefresh(mozilla::TimeStamp aTime) = 0;
 };
 
-class nsRefreshDriver : public nsITimerCallback {
+class nsRefreshDriver MOZ_FINAL : public nsITimerCallback {
 public:
   nsRefreshDriver(nsPresContext *aPresContext);
   ~nsRefreshDriver();
diff --git a/layout/base/nsStyleSheetService.h b/layout/base/nsStyleSheetService.h
index acc6735d7483..7cd7f63b6552 100644
--- a/layout/base/nsStyleSheetService.h
+++ b/layout/base/nsStyleSheetService.h
@@ -11,6 +11,7 @@
 #include "nsIStyleSheetService.h"
 #include "nsCOMArray.h"
 #include "nsIStyleSheet.h"
+#include "mozilla/Attributes.h"
 
 class nsISimpleEnumerator;
 class nsICategoryManager;
@@ -21,7 +22,7 @@ class nsICategoryManager;
 #define NS_STYLESHEETSERVICE_CONTRACTID \
   "@mozilla.org/content/style-sheet-service;1"
 
-class nsStyleSheetService : public nsIStyleSheetService
+class nsStyleSheetService MOZ_FINAL : public nsIStyleSheetService
 {
  public:
   nsStyleSheetService() NS_HIDDEN;
diff --git a/layout/build/nsLayoutModule.cpp b/layout/build/nsLayoutModule.cpp
index c6010235e3d5..def05a4306f5 100644
--- a/layout/build/nsLayoutModule.cpp
+++ b/layout/build/nsLayoutModule.cpp
@@ -52,6 +52,7 @@
 #include "ThirdPartyUtil.h"
 #include "mozilla/Services.h"
 #include "nsStructuredCloneContainer.h"
+#include "mozilla/Attributes.h"
 
 #include "nsIEventListenerService.h"
 #include "nsIFrameMessageManager.h"
@@ -281,7 +282,7 @@ NS_GENERIC_FACTORY_CONSTRUCTOR(SmsRequestManager)
 // references to objects in other component libraries that have already been
 // shutdown (and possibly unloaded if 60709 is ever fixed).
 
-class LayoutShutdownObserver : public nsIObserver
+class LayoutShutdownObserver MOZ_FINAL : public nsIObserver
 {
 public:
   NS_DECL_ISUPPORTS
diff --git a/layout/forms/nsFileControlFrame.h b/layout/forms/nsFileControlFrame.h
index d5e3931ae48c..923991851348 100644
--- a/layout/forms/nsFileControlFrame.h
+++ b/layout/forms/nsFileControlFrame.h
@@ -12,7 +12,6 @@
 #include "nsIAnonymousContentCreator.h"
 #include "nsICapturePicker.h"
 #include "nsCOMPtr.h"
-#include "mozilla/Attributes.h"
 
 class nsTextControlFrame;
 class nsIDOMDragEvent;
@@ -78,13 +77,14 @@ protected:
   
   class MouseListener;
   friend class MouseListener;
-  class MouseListener MOZ_FINAL : public nsIDOMEventListener {
+  class MouseListener : public nsIDOMEventListener {
   public:
     NS_DECL_ISUPPORTS
     
     MouseListener(nsFileControlFrame* aFrame)
      : mFrame(aFrame) 
     {}
+    virtual ~MouseListener() {}
 
     void ForgetFrame() {
       mFrame = nsnull;
diff --git a/layout/forms/nsListControlFrame.cpp b/layout/forms/nsListControlFrame.cpp
index c67e062855c8..74d4ee836b51 100644
--- a/layout/forms/nsListControlFrame.cpp
+++ b/layout/forms/nsListControlFrame.cpp
@@ -48,6 +48,7 @@
 #include "nsDisplayList.h"
 #include "nsContentUtils.h"
 #include "mozilla/LookAndFeel.h"
+#include "mozilla/Attributes.h"
 
 using namespace mozilla;
 
@@ -74,7 +75,7 @@ DOMTimeStamp nsListControlFrame::gLastKeyTime = 0;
  * Frames are not refcounted so they can't be used as event listeners.
  *****************************************************************************/
 
-class nsListEventListener : public nsIDOMEventListener
+class nsListEventListener MOZ_FINAL : public nsIDOMEventListener
 {
 public:
   nsListEventListener(nsListControlFrame *aFrame)
diff --git a/layout/generic/nsAutoCopyListener.h b/layout/generic/nsAutoCopyListener.h
index ca5f24d8d4b4..ca33cdc9a1b6 100644
--- a/layout/generic/nsAutoCopyListener.h
+++ b/layout/generic/nsAutoCopyListener.h
@@ -8,8 +8,9 @@
 
 #include "nsISelectionListener.h"
 #include "nsISelectionPrivate.h"
+#include "mozilla/Attributes.h"
 
-class nsAutoCopyListener : public nsISelectionListener
+class nsAutoCopyListener MOZ_FINAL : public nsISelectionListener
 {
 public:
   NS_DECL_ISUPPORTS
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 61472e7490fa..52e1c384dc71 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -51,6 +51,7 @@
 #include "nsSMILKeySpline.h"
 #include "nsSubDocumentFrame.h"
 #include "nsSVGOuterSVGFrame.h"
+#include "mozilla/Attributes.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -1281,7 +1282,7 @@ const double kCurrentVelocityWeighting = 0.25;
 const double kStopDecelerationWeighting = 0.4;
 
 // AsyncScroll has ref counting.
-class nsGfxScrollFrameInner::AsyncScroll : public nsARefreshObserver {
+class nsGfxScrollFrameInner::AsyncScroll MOZ_FINAL : public nsARefreshObserver {
 public:
   typedef mozilla::TimeStamp TimeStamp;
   typedef mozilla::TimeDuration TimeDuration;
@@ -1553,7 +1554,7 @@ IsSmoothScrollingEnabled()
   return Preferences::GetBool(SMOOTH_SCROLL_PREF_NAME, false);
 }
 
-class ScrollFrameActivityTracker : public nsExpirationTracker<nsGfxScrollFrameInner,4> {
+class ScrollFrameActivityTracker MOZ_FINAL : public nsExpirationTracker<nsGfxScrollFrameInner,4> {
 public:
   // Wait for 3-4s between scrolls before we remove our layers.
   // That's 4 generations of 1s each.
diff --git a/layout/generic/nsImageFrame.h b/layout/generic/nsImageFrame.h
index 81450f94d6d4..6f0f4413c3c6 100644
--- a/layout/generic/nsImageFrame.h
+++ b/layout/generic/nsImageFrame.h
@@ -17,6 +17,7 @@
 
 #include "nsDisplayList.h"
 #include "imgIContainer.h"
+#include "mozilla/Attributes.h"
 
 class nsIFrame;
 class nsImageMap;
@@ -309,8 +310,8 @@ private:
   nsresult LoadIcon(const nsAString& aSpec, nsPresContext *aPresContext,
                     imgIRequest **aRequest);
 
-  class IconLoad : public nsIObserver,
-                   public imgIDecoderObserver {
+  class IconLoad MOZ_FINAL : public nsIObserver,
+                             public imgIDecoderObserver {
     // private class that wraps the data and logic needed for
     // broken image and loading image icons
   public:
diff --git a/layout/generic/nsTextFrameThebes.cpp b/layout/generic/nsTextFrameThebes.cpp
index 80ba15f08d79..2bcbfc26c79c 100644
--- a/layout/generic/nsTextFrameThebes.cpp
+++ b/layout/generic/nsTextFrameThebes.cpp
@@ -71,6 +71,7 @@
 #include "mozilla/dom/Element.h"
 #include "mozilla/Util.h" // for DebugOnly
 #include "mozilla/LookAndFeel.h"
+#include "mozilla/Attributes.h"
 
 #include "sampler.h"
 
@@ -841,7 +842,7 @@ public:
     }
   };
 
-  class BreakSink : public nsILineBreakSink {
+  class BreakSink MOZ_FINAL : public nsILineBreakSink {
   public:
     BreakSink(gfxTextRun* aTextRun, gfxContext* aContext, PRUint32 aOffsetIntoTextRun,
               bool aExistingTextRun) :
diff --git a/layout/mathml/nsMathMLmactionFrame.h b/layout/mathml/nsMathMLmactionFrame.h
index 0ff4bde93bdf..dec23b204583 100644
--- a/layout/mathml/nsMathMLmactionFrame.h
+++ b/layout/mathml/nsMathMLmactionFrame.h
@@ -9,6 +9,7 @@
 #include "nsCOMPtr.h"
 #include "nsMathMLContainerFrame.h"
 #include "nsIDOMEventListener.h"
+#include "mozilla/Attributes.h"
 
 //
 // <maction> -- bind actions to a subexpression
@@ -60,7 +61,7 @@ private:
   void MouseOver();
   void MouseOut();
 
-  class MouseListener : public nsIDOMEventListener
+  class MouseListener MOZ_FINAL : public nsIDOMEventListener
   {
     NS_DECL_ISUPPORTS
     NS_DECL_NSIDOMEVENTLISTENER
diff --git a/layout/style/nsDOMMediaQueryList.h b/layout/style/nsDOMMediaQueryList.h
index de9f6d508a34..ba10c42822d2 100644
--- a/layout/style/nsDOMMediaQueryList.h
+++ b/layout/style/nsDOMMediaQueryList.h
@@ -14,12 +14,13 @@
 #include "nsCOMPtr.h"
 #include "nsTArray.h"
 #include "prclist.h"
+#include "mozilla/Attributes.h"
 
 class nsPresContext;
 class nsMediaList;
 
-class nsDOMMediaQueryList : public nsIDOMMediaQueryList,
-                            public PRCList
+class nsDOMMediaQueryList MOZ_FINAL : public nsIDOMMediaQueryList,
+                                      public PRCList
 {
 public:
   // The caller who constructs is responsible for calling Evaluate
diff --git a/layout/style/nsHTMLCSSStyleSheet.h b/layout/style/nsHTMLCSSStyleSheet.h
index 793cb7db54a8..e9cfa1d04f8f 100644
--- a/layout/style/nsHTMLCSSStyleSheet.h
+++ b/layout/style/nsHTMLCSSStyleSheet.h
@@ -15,8 +15,8 @@
 #include "nsIStyleSheet.h"
 #include "nsIStyleRuleProcessor.h"
 
-class nsHTMLCSSStyleSheet : public nsIStyleSheet,
-                            public nsIStyleRuleProcessor {
+class nsHTMLCSSStyleSheet MOZ_FINAL : public nsIStyleSheet,
+                                      public nsIStyleRuleProcessor {
 public:
   nsHTMLCSSStyleSheet();
 
diff --git a/layout/style/nsHTMLStyleSheet.h b/layout/style/nsHTMLStyleSheet.h
index 2c4130600c9c..804a77e39e5f 100644
--- a/layout/style/nsHTMLStyleSheet.h
+++ b/layout/style/nsHTMLStyleSheet.h
@@ -20,9 +20,13 @@
 #include "pldhash.h"
 #include "nsCOMPtr.h"
 #include "nsColor.h"
+#include "mozilla/Attributes.h"
+
 class nsMappedAttributes;
 
-class nsHTMLStyleSheet : public nsIStyleSheet, public nsIStyleRuleProcessor {
+class nsHTMLStyleSheet MOZ_FINAL : public nsIStyleSheet,
+                                   public nsIStyleRuleProcessor
+{
 public:
   nsHTMLStyleSheet(void);
   nsresult Init();
@@ -83,7 +87,7 @@ private:
 
   class HTMLColorRule;
   friend class HTMLColorRule;
-  class HTMLColorRule : public nsIStyleRule {
+  class HTMLColorRule MOZ_FINAL : public nsIStyleRule {
   public:
     HTMLColorRule() {}
 
@@ -103,9 +107,10 @@ private:
 
   class GenericTableRule;
   friend class GenericTableRule;
-  class GenericTableRule: public nsIStyleRule {
+  class GenericTableRule : public nsIStyleRule {
   public:
     GenericTableRule() {}
+    virtual ~GenericTableRule() {}
 
     NS_DECL_ISUPPORTS
 
@@ -119,7 +124,7 @@ private:
   // this rule handles <th> inheritance
   class TableTHRule;
   friend class TableTHRule;
-  class TableTHRule: public GenericTableRule {
+  class TableTHRule MOZ_FINAL : public GenericTableRule {
   public:
     TableTHRule() {}
 
@@ -127,7 +132,7 @@ private:
   };
 
   // Rule to handle quirk table colors
-  class TableQuirkColorRule : public GenericTableRule {
+  class TableQuirkColorRule MOZ_FINAL : public GenericTableRule {
   public:
     TableQuirkColorRule() {}
 
diff --git a/layout/style/nsIMediaList.h b/layout/style/nsIMediaList.h
index 9839b4a660b6..bfa50fd5d4c4 100644
--- a/layout/style/nsIMediaList.h
+++ b/layout/style/nsIMediaList.h
@@ -16,6 +16,7 @@
 #include "nsTArray.h"
 #include "nsIAtom.h"
 #include "nsCSSValue.h"
+#include "mozilla/Attributes.h"
 
 class nsPresContext;
 class nsCSSStyleSheet;
@@ -142,7 +143,7 @@ private:
   nsTArray<nsMediaExpression> mExpressions;
 };
 
-class nsMediaList : public nsIDOMMediaList {
+class nsMediaList MOZ_FINAL : public nsIDOMMediaList {
 public:
   nsMediaList();
 
diff --git a/layout/style/nsLayoutStylesheetCache.h b/layout/style/nsLayoutStylesheetCache.h
index e8b78a7b65a5..7d697f348894 100644
--- a/layout/style/nsLayoutStylesheetCache.h
+++ b/layout/style/nsLayoutStylesheetCache.h
@@ -9,6 +9,7 @@
 #include "nsCOMPtr.h"
 #include "nsIObserver.h"
 #include "nsAutoPtr.h"
+#include "mozilla/Attributes.h"
 
 class nsIFile;
 class nsCSSStyleSheet;
@@ -22,7 +23,7 @@ class Loader;
 
 class nsIMemoryReporter;
 
-class nsLayoutStylesheetCache
+class nsLayoutStylesheetCache MOZ_FINAL
  : public nsIObserver
 {
   NS_DECL_ISUPPORTS
diff --git a/layout/style/nsStyleSet.h b/layout/style/nsStyleSet.h
index 87ac1050b928..a91e90563753 100644
--- a/layout/style/nsStyleSet.h
+++ b/layout/style/nsStyleSet.h
@@ -24,6 +24,7 @@
 #include "nsIStyleRule.h"
 #include "nsCSSPseudoElements.h"
 #include "nsCSSAnonBoxes.h"
+#include "mozilla/Attributes.h"
 
 class nsIURI;
 class nsCSSFontFaceRule;
@@ -32,7 +33,7 @@ class nsRuleWalker;
 struct RuleProcessorData;
 struct TreeMatchContext;
 
-class nsEmptyStyleRule : public nsIStyleRule
+class nsEmptyStyleRule MOZ_FINAL : public nsIStyleRule
 {
   NS_DECL_ISUPPORTS
   virtual void MapRuleInfoInto(nsRuleData* aRuleData);
@@ -41,7 +42,7 @@ class nsEmptyStyleRule : public nsIStyleRule
 #endif
 };
 
-class nsInitialStyleRule : public nsIStyleRule
+class nsInitialStyleRule MOZ_FINAL : public nsIStyleRule
 {
   NS_DECL_ISUPPORTS
   virtual void MapRuleInfoInto(nsRuleData* aRuleData);
diff --git a/layout/xul/base/public/nsXULPopupManager.h b/layout/xul/base/public/nsXULPopupManager.h
index f7c2b607473f..fea4b2747c4a 100644
--- a/layout/xul/base/public/nsXULPopupManager.h
+++ b/layout/xul/base/public/nsXULPopupManager.h
@@ -22,6 +22,7 @@
 #include "nsIReflowCallback.h"
 #include "nsThreadUtils.h"
 #include "nsStyleConsts.h"
+#include "mozilla/Attributes.h"
 
 // X.h defines KeyPress
 #ifdef KeyPress
@@ -268,10 +269,10 @@ private:
   CloseMenuMode mCloseMenuMode;
 };
 
-class nsXULPopupManager : public nsIDOMEventListener,
-                          public nsIRollupListener,
-                          public nsITimerCallback,
-                          public nsIObserver
+class nsXULPopupManager MOZ_FINAL : public nsIDOMEventListener,
+                                    public nsIRollupListener,
+                                    public nsITimerCallback,
+                                    public nsIObserver
 {
 
 public:
diff --git a/layout/xul/base/src/nsMenuFrame.h b/layout/xul/base/src/nsMenuFrame.h
index ea6276e14f7b..dc4b7e49acff 100644
--- a/layout/xul/base/src/nsMenuFrame.h
+++ b/layout/xul/base/src/nsMenuFrame.h
@@ -21,6 +21,7 @@
 #include "nsXULPopupManager.h"
 #include "nsITimer.h"
 #include "nsIContent.h"
+#include "mozilla/Attributes.h"
 
 nsIFrame* NS_NewMenuFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMenuItemFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
@@ -55,7 +56,7 @@ class nsMenuFrame;
  * to it. The callback is delegated to the contained nsMenuFrame as long as
  * the contained nsMenuFrame has not been destroyed.
  */
-class nsMenuTimerMediator : public nsITimerCallback
+class nsMenuTimerMediator MOZ_FINAL : public nsITimerCallback
 {
 public:
   nsMenuTimerMediator(nsMenuFrame* aFrame);
diff --git a/layout/xul/base/src/nsXULTooltipListener.h b/layout/xul/base/src/nsXULTooltipListener.h
index 9f044a620799..1cf4395eb3e0 100644
--- a/layout/xul/base/src/nsXULTooltipListener.h
+++ b/layout/xul/base/src/nsXULTooltipListener.h
@@ -18,8 +18,9 @@
 #include "nsITreeColumns.h"
 #endif
 #include "nsWeakPtr.h"
+#include "mozilla/Attributes.h"
 
-class nsXULTooltipListener : public nsIDOMEventListener
+class nsXULTooltipListener MOZ_FINAL : public nsIDOMEventListener
 {
 public:
   NS_DECL_ISUPPORTS
diff --git a/layout/xul/base/src/tree/src/nsTreeSelection.h b/layout/xul/base/src/tree/src/nsTreeSelection.h
index 5701bc3fed2b..14788a64c2e2 100644
--- a/layout/xul/base/src/tree/src/nsTreeSelection.h
+++ b/layout/xul/base/src/tree/src/nsTreeSelection.h
@@ -11,11 +11,12 @@
 #include "nsITreeColumns.h"
 #include "nsITimer.h"
 #include "nsCycleCollectionParticipant.h"
+#include "mozilla/Attributes.h"
 
 class nsITreeBoxObject;
 struct nsTreeRange;
 
-class nsTreeSelection : public nsINativeTreeSelection
+class nsTreeSelection MOZ_FINAL : public nsINativeTreeSelection
 {
 public:
   nsTreeSelection(nsITreeBoxObject* aTree);