diff --git a/gfx/2d/2D.h b/gfx/2d/2D.h
index 5ca53977cecf..021853298084 100644
--- a/gfx/2d/2D.h
+++ b/gfx/2d/2D.h
@@ -1464,6 +1464,8 @@ class DrawTargetCapture : public DrawTarget
 public:
   virtual bool IsCaptureDT() const override { return true; }
 
+  virtual void Dump() = 0;
+
   /**
    * Returns true if the recording only contains FillGlyph calls with
    * a single font and color. Returns the list of Glyphs along with
diff --git a/gfx/2d/CaptureCommandList.h b/gfx/2d/CaptureCommandList.h
index 6c1b406eb5dd..b514364ccbf0 100644
--- a/gfx/2d/CaptureCommandList.h
+++ b/gfx/2d/CaptureCommandList.h
@@ -12,6 +12,7 @@
 #include <vector>
 
 #include "DrawCommand.h"
+#include "Logging.h"
 
 namespace mozilla {
 namespace gfx {
@@ -87,6 +88,15 @@ public:
     uint8_t* mEnd;
   };
 
+  void Log(TreeLog& aStream)
+  {
+    for (iterator iter(*this); !iter.Done(); iter.Next()) {
+      DrawingCommand* cmd = iter.Get();
+      cmd->Log(aStream);
+      aStream << "\n";
+    }
+  }
+
 private:
   CaptureCommandList(const CaptureCommandList& aOther) = delete;
   void operator =(const CaptureCommandList& aOther) = delete;
diff --git a/gfx/2d/DrawCommand.h b/gfx/2d/DrawCommand.h
index fc9dedef0edd..07dca044a857 100644
--- a/gfx/2d/DrawCommand.h
+++ b/gfx/2d/DrawCommand.h
@@ -14,6 +14,7 @@
 #include "Filters.h"
 #include <vector>
 #include "FilterNodeCapture.h"
+#include "Logging.h"
 
 namespace mozilla {
 namespace gfx {
@@ -55,6 +56,7 @@ public:
   virtual void ExecuteOnDT(DrawTarget* aDT, const Matrix* aTransform = nullptr) const = 0;
   virtual bool GetAffectedRect(Rect& aDeviceRect, const Matrix& aTransform) const { return false; }
   virtual void CloneInto(CaptureCommandList* aList) = 0;
+  virtual void Log(TreeLog& aLog) const = 0;
 
   CommandType GetType() { return mType; }
 
diff --git a/gfx/2d/DrawCommands.h b/gfx/2d/DrawCommands.h
index fcc11fd10433..d363b39b18cc 100644
--- a/gfx/2d/DrawCommands.h
+++ b/gfx/2d/DrawCommands.h
@@ -16,6 +16,7 @@
 #include "CaptureCommandList.h"
 #include "DrawCommand.h"
 #include "FilterNodeCapture.h"
+#include "Logging.h"
 
 namespace mozilla {
 namespace gfx {
@@ -81,6 +82,16 @@ public:
     reinterpret_cast<Pattern*>(mPattern)->~Pattern();
   }
 
+  Pattern* Get()
+  {
+    return reinterpret_cast<Pattern*>(mPattern);
+  }
+
+  const Pattern* Get() const
+  {
+    return reinterpret_cast<const Pattern*>(mPattern);
+  }
+
   operator Pattern&()
   {
     return *reinterpret_cast<Pattern*>(mPattern);
@@ -135,6 +146,16 @@ public:
     aDT->DrawSurface(mSurface, mDest, mSource, mSurfOptions, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[DrawSurface surf=" << mSurface;
+    aStream << " dest=" << mDest;
+    aStream << " src=" << mSource;
+    aStream << " surfOpt=" << mSurfOptions;
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::DRAWSURFACE;
 
@@ -175,6 +196,17 @@ public:
     aDT->DrawSurfaceWithShadow(mSurface, mDest, mColor, mOffset, mSigma, mOperator);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[DrawSurfaceWithShadow surf=" << mSurface;
+    aStream << " dest=" << mDest;
+    aStream << " color=" << mColor;
+    aStream << " offset=" << mOffset;
+    aStream << " sigma=" << mSigma;
+    aStream << " op=" << mOperator;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::DRAWSURFACEWITHSHADOW;
 
@@ -212,6 +244,15 @@ public:
     aDT->DrawFilter(filter, mSourceRect, mDestPoint, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[DrawFilter surf=" << mFilter;
+    aStream << " src=" << mSourceRect;
+    aStream << " dest=" << mDestPoint;
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::DRAWFILTER;
 
@@ -241,6 +282,11 @@ public:
     aDT->ClearRect(mRect);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[ClearRect rect=" << mRect << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::CLEARRECT;
 
@@ -276,6 +322,14 @@ public:
     aDT->CopySurface(mSurface, mSourceRect, IntPoint(uint32_t(dest.x), uint32_t(dest.y)));
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[CopySurface surf=" << mSurface;
+    aStream << " src=" << mSourceRect;
+    aStream << " dest=" << mDestination;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::COPYSURFACE;
 
@@ -314,6 +368,14 @@ public:
     return true;
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[FillRect rect=" << mRect;
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::FILLRECT;
 
@@ -347,6 +409,14 @@ public:
     aDT->StrokeRect(mRect, mPattern, mStrokeOptions, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[StrokeRect rect=" << mRect;
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::STROKERECT;
 
@@ -382,6 +452,15 @@ public:
     aDT->StrokeLine(mStart, mEnd, mPattern, mStrokeOptions, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[StrokeLine start=" << mStart;
+    aStream << " end=" << mEnd;
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::STROKELINE;
 
@@ -421,6 +500,14 @@ public:
     return true;
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[FillCommand path=" << mPath;
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::FILL;
 
@@ -501,6 +588,14 @@ public:
     return true;
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[Stroke path=" << mPath;
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::STROKE;
 
@@ -544,6 +639,15 @@ public:
     aDT->FillGlyphs(mFont, buf, mPattern, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[FillGlyphs font=" << mFont;
+    aStream << " glyphCount=" << mGlyphs.size();
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::FILLGLYPHS;
 
@@ -589,6 +693,15 @@ public:
     aDT->StrokeGlyphs(mFont, buf, mPattern, mStrokeOptions, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[StrokeGlyphs font=" << mFont;
+    aStream << " glyphCount=" << mGlyphs.size();
+    aStream << " pattern=" << mPattern.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::STROKEGLYPHS;
 
@@ -622,6 +735,14 @@ public:
     aDT->Mask(mSource, mMask, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[Mask source=" << mSource.Get();
+    aStream << " mask=" << mMask.Get();
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::MASK;
 
@@ -656,6 +777,15 @@ public:
     aDT->MaskSurface(mSource, mMask, mOffset, mOptions);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[Mask source=" << mSource.Get();
+    aStream << " mask=" << mMask;
+    aStream << " offset=" << &mOffset;
+    aStream << " opt=" << mOptions;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::MASKSURFACE;
 
@@ -685,6 +815,11 @@ public:
     aDT->PushClip(mPath);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[PushClip path=" << mPath << "]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::PUSHCLIP;
 
@@ -711,6 +846,11 @@ public:
     aDT->PushClipRect(mRect);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[PushClipRect rect=" << mRect << "]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::PUSHCLIPRECT;
 
@@ -748,6 +888,17 @@ public:
                    mMaskTransform, mBounds, mCopyBackground);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[PushLayer opaque=" << mOpaque;
+    aStream << " opacity=" << mOpacity;
+    aStream << " mask=" << mMask;
+    aStream << " maskTransform=" << mMaskTransform;
+    aStream << " bounds=" << mBounds;
+    aStream << " copyBackground=" << mCopyBackground;
+    aStream << "]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::PUSHLAYER;
 
@@ -778,6 +929,11 @@ public:
     aDT->PopClip();
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[PopClip]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::POPCLIP;
 };
@@ -800,6 +956,11 @@ public:
     aDT->PopLayer();
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[PopLayer]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::POPLAYER;
 };
@@ -828,6 +989,11 @@ public:
     }
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[SetTransform transform=" << mTransform << "]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::SETTRANSFORM;
 
@@ -855,6 +1021,11 @@ public:
     aDT->SetPermitSubpixelAA(mPermitSubpixelAA);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[SetPermitSubpixelAA permitSubpixelAA=" << mPermitSubpixelAA << "]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::SETPERMITSUBPIXELAA;
 
@@ -880,6 +1051,11 @@ public:
     aDT->Flush();
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[Flush]";
+  }
+
   static const bool AffectsSnapshot = false;
   static const CommandType Type = CommandType::FLUSH;
 };
@@ -902,6 +1078,11 @@ public:
     aDT->Blur(mBlur);
   }
 
+  void Log(TreeLog& aStream) const override
+  {
+    aStream << "[Blur]";
+  }
+
   static const bool AffectsSnapshot = true;
   static const CommandType Type = CommandType::BLUR;
 
diff --git a/gfx/2d/DrawTargetCapture.cpp b/gfx/2d/DrawTargetCapture.cpp
index cca28958b93b..efdffa0b02ca 100644
--- a/gfx/2d/DrawTargetCapture.cpp
+++ b/gfx/2d/DrawTargetCapture.cpp
@@ -443,5 +443,15 @@ DrawTargetCaptureImpl::CreateFilter(FilterType aType)
   }
 }
 
+void
+DrawTargetCaptureImpl::Dump()
+{
+  TreeLog output;
+  output << "DrawTargetCapture(" << (void*)(this) << ")\n";
+  TreeAutoIndent indent(output);
+  mCommands.Log(output);
+  output << "\n";
+}
+
 } // namespace gfx
 } // namespace mozilla
diff --git a/gfx/2d/DrawTargetCapture.h b/gfx/2d/DrawTargetCapture.h
index 756779b87721..8661fcd7ac2b 100644
--- a/gfx/2d/DrawTargetCapture.h
+++ b/gfx/2d/DrawTargetCapture.h
@@ -149,6 +149,8 @@ public:
 
   bool ContainsOnlyColoredGlyphs(RefPtr<ScaledFont>& aScaledFont, Color& aColor, std::vector<Glyph>& aGlyphs) override;
 
+  void Dump() override;
+
 protected:
   virtual ~DrawTargetCaptureImpl();
 
diff --git a/gfx/2d/Logging.h b/gfx/2d/Logging.h
index 012a0c744fd0..ee5b370bbcbe 100644
--- a/gfx/2d/Logging.h
+++ b/gfx/2d/Logging.h
@@ -20,6 +20,7 @@
 #if defined(MOZ_WIDGET_ANDROID)
 #include "nsDebug.h"
 #endif
+#include "2D.h"
 #include "Point.h"
 #include "BaseRect.h"
 #include "Matrix.h"
@@ -357,6 +358,12 @@ public:
     }
     return *this;
   }
+  Log &operator <<(const Color& aColor) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "Color(" << aColor.r << ", " << aColor.g << ", " << aColor.b << ", " << aColor.a << ")";
+    }
+    return *this;
+  }
   template <typename T, typename Sub, typename Coord>
   Log &operator <<(const BasePoint<T, Sub, Coord>& aPoint) {
     if (MOZ_UNLIKELY(LogIt())) {
@@ -394,6 +401,205 @@ public:
     return *this;
   }
 
+  Log &operator<<(const SourceSurface* aSurface) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "SourceSurface(" << (void*)(aSurface) << ")";
+    }
+    return *this;
+  }
+  Log &operator<<(const Path* aPath) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "Path(" << (void*)(aPath) << ")";
+    }
+    return *this;
+  }
+  Log &operator<<(const Pattern* aPattern) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "Pattern(" << (void*)(aPattern) << ")";
+    }
+    return *this;
+  }
+  Log &operator<<(const ScaledFont* aFont) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "ScaledFont(" << (void*)(aFont) << ")";
+    }
+    return *this;
+  }
+  Log &operator<<(const FilterNode* aFilter) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "FilterNode(" << (void*)(aFilter) << ")";
+    }
+    return *this;
+  }
+  Log &operator<<(const DrawOptions& aOptions) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "DrawOptions(" << aOptions.mAlpha << ", ";
+      (*this) << aOptions.mCompositionOp;
+      mMessage << ", ";
+      (*this) << aOptions.mAntialiasMode;
+      mMessage << ")";
+    }
+    return *this;
+  }
+  Log &operator<<(const DrawSurfaceOptions& aOptions) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      mMessage << "DrawSurfaceOptions(";
+      (*this) << aOptions.mSamplingFilter;
+      mMessage << ", ";
+      (*this) << aOptions.mSamplingBounds;
+      mMessage << ")";
+    }
+    return *this;
+  }
+
+  Log& operator<<(SamplingBounds aBounds) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      switch(aBounds) {
+        case SamplingBounds::UNBOUNDED:
+          mMessage << "SamplingBounds::UNBOUNDED";
+          break;
+        case SamplingBounds::BOUNDED:
+          mMessage << "SamplingBounds::BOUNDED";
+          break;
+        default:
+          mMessage << "Invalid SamplingBounds (" << (int)aBounds << ")";
+          break;
+      }
+    }
+    return *this;
+  }
+  Log& operator<<(SamplingFilter aFilter) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      switch(aFilter) {
+        case SamplingFilter::GOOD:
+          mMessage << "SamplingFilter::GOOD";
+          break;
+        case SamplingFilter::LINEAR:
+          mMessage << "SamplingFilter::LINEAR";
+          break;
+        case SamplingFilter::POINT:
+          mMessage << "SamplingFilter::POINT";
+          break;
+        default:
+          mMessage << "Invalid SamplingFilter (" << (int)aFilter << ")";
+          break;
+      }
+    }
+    return *this;
+  }
+  Log& operator<<(AntialiasMode aMode) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      switch(aMode) {
+        case AntialiasMode::NONE:
+          mMessage << "AntialiasMode::NONE";
+          break;
+        case AntialiasMode::GRAY:
+          mMessage << "AntialiasMode::GRAY";
+          break;
+        case AntialiasMode::SUBPIXEL:
+          mMessage << "AntialiasMode::SUBPIXEL";
+          break;
+        case AntialiasMode::DEFAULT:
+          mMessage << "AntialiasMode::DEFAULT";
+          break;
+        default:
+          mMessage << "Invalid AntialiasMode (" << (int)aMode << ")";
+          break;
+      }
+    }
+    return *this;
+  }
+  Log& operator<<(CompositionOp aOp) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      switch(aOp) {
+        case CompositionOp::OP_OVER:
+          mMessage << "CompositionOp::OP_OVER";
+          break;
+        case CompositionOp::OP_ADD:
+          mMessage << "CompositionOp::OP_ADD";
+          break;
+        case CompositionOp::OP_ATOP:
+          mMessage << "CompositionOp::OP_ATOP";
+          break;
+        case CompositionOp::OP_OUT:
+          mMessage << "CompositionOp::OP_OUT";
+          break;
+        case CompositionOp::OP_IN:
+          mMessage << "CompositionOp::OP_IN";
+          break;
+        case CompositionOp::OP_SOURCE:
+          mMessage << "CompositionOp::OP_SOURCE";
+          break;
+        case CompositionOp::OP_DEST_IN:
+          mMessage << "CompositionOp::OP_DEST_IN";
+          break;
+        case CompositionOp::OP_DEST_OUT:
+          mMessage << "CompositionOp::OP_DEST_OUT";
+          break;
+        case CompositionOp::OP_DEST_OVER:
+          mMessage << "CompositionOp::OP_DEST_OVER";
+          break;
+        case CompositionOp::OP_DEST_ATOP:
+          mMessage << "CompositionOp::OP_DEST_ATOP";
+          break;
+        case CompositionOp::OP_XOR:
+          mMessage << "CompositionOp::OP_XOR";
+          break;
+        case CompositionOp::OP_MULTIPLY:
+          mMessage << "CompositionOp::OP_MULTIPLY";
+          break;
+        case CompositionOp::OP_SCREEN:
+          mMessage << "CompositionOp::OP_SCREEN";
+          break;
+        case CompositionOp::OP_OVERLAY:
+          mMessage << "CompositionOp::OP_OVERLAY";
+          break;
+        case CompositionOp::OP_DARKEN:
+          mMessage << "CompositionOp::OP_DARKEN";
+          break;
+        case CompositionOp::OP_LIGHTEN:
+          mMessage << "CompositionOp::OP_LIGHTEN";
+          break;
+        case CompositionOp::OP_COLOR_DODGE:
+          mMessage << "CompositionOp::OP_COLOR_DODGE";
+          break;
+        case CompositionOp::OP_COLOR_BURN:
+          mMessage << "CompositionOp::OP_COLOR_BURN";
+          break;
+        case CompositionOp::OP_HARD_LIGHT:
+          mMessage << "CompositionOp::OP_HARD_LIGHT";
+          break;
+        case CompositionOp::OP_SOFT_LIGHT:
+          mMessage << "CompositionOp::OP_SOFT_LIGHT";
+          break;
+        case CompositionOp::OP_DIFFERENCE:
+          mMessage << "CompositionOp::OP_DIFFERENCE";
+          break;
+        case CompositionOp::OP_EXCLUSION:
+          mMessage << "CompositionOp::OP_EXCLUSION";
+          break;
+        case CompositionOp::OP_HUE:
+          mMessage << "CompositionOp::OP_HUE";
+          break;
+        case CompositionOp::OP_SATURATION:
+          mMessage << "CompositionOp::OP_SATURATION";
+          break;
+        case CompositionOp::OP_COLOR:
+          mMessage << "CompositionOp::OP_COLOR";
+          break;
+        case CompositionOp::OP_LUMINOSITY:
+          mMessage << "CompositionOp::OP_LUMINOSITY";
+          break;
+        case CompositionOp::OP_COUNT:
+          mMessage << "CompositionOp::OP_COUNT";
+          break;
+        default:
+          mMessage << "Invalid CompositionOp (" << (int)aOp << ")";
+          break;
+      }
+    }
+    return *this;
+  }
   Log& operator<<(SurfaceFormat aFormat) {
     if (MOZ_UNLIKELY(LogIt())) {
       switch(aFormat) {
@@ -637,7 +843,10 @@ public:
       return *this;
     }
     if (mStartOfLine) {
-      mLog << '[' << mPrefix << "] " << std::string(mDepth * INDENT_PER_LEVEL, ' ');
+      if (!mPrefix.empty()) {
+        mLog << '[' << mPrefix << "] ";
+      }
+      mLog << std::string(mDepth * INDENT_PER_LEVEL, ' ');
       mStartOfLine = false;
     }
     mLog << aObject;
diff --git a/layout/style/ServoBindings.toml b/layout/style/ServoBindings.toml
index 2f3f78bab91c..1cb34fbf4d64 100644
--- a/layout/style/ServoBindings.toml
+++ b/layout/style/ServoBindings.toml
@@ -389,6 +389,7 @@ opaque-types = [
     "mozilla::dom::Optional",
     "mozilla::dom::OwningNodeOrString_Value",
     "mozilla::dom::Nullable",
+    "mozilla::external::AtomicRefCounted",
     "RefPtr_Proxy",
     "RefPtr_Proxy_member_function",
     "nsAutoPtr_Proxy",