--- a/dom/canvas/BasicRenderingContext2D.cpp
+++ b/dom/canvas/BasicRenderingContext2D.cpp
@@ -155,16 +155,106 @@ BasicRenderingContext2D::SetTransformInt
 
 void
 BasicRenderingContext2D::ResetTransform(ErrorResult& aError)
 {
   SetTransform(1.0, 0.0, 0.0, 1.0, 0.0, 0.0, aError);
 }
 
 //
+// compositing
+//
+
+void
+BasicRenderingContext2D::SetGlobalCompositeOperation(const nsAString& aOp,
+                                                     ErrorResult& aError)
+{
+  CompositionOp comp_op;
+
+#define CANVAS_OP_TO_GFX_OP(cvsop, op2d) \
+  if (aOp.EqualsLiteral(cvsop))   \
+    comp_op = CompositionOp::OP_##op2d;
+
+  CANVAS_OP_TO_GFX_OP("copy", SOURCE)
+  else CANVAS_OP_TO_GFX_OP("source-atop", ATOP)
+  else CANVAS_OP_TO_GFX_OP("source-in", IN)
+  else CANVAS_OP_TO_GFX_OP("source-out", OUT)
+  else CANVAS_OP_TO_GFX_OP("source-over", OVER)
+  else CANVAS_OP_TO_GFX_OP("destination-in", DEST_IN)
+  else CANVAS_OP_TO_GFX_OP("destination-out", DEST_OUT)
+  else CANVAS_OP_TO_GFX_OP("destination-over", DEST_OVER)
+  else CANVAS_OP_TO_GFX_OP("destination-atop", DEST_ATOP)
+  else CANVAS_OP_TO_GFX_OP("lighter", ADD)
+  else CANVAS_OP_TO_GFX_OP("xor", XOR)
+  else CANVAS_OP_TO_GFX_OP("multiply", MULTIPLY)
+  else CANVAS_OP_TO_GFX_OP("screen", SCREEN)
+  else CANVAS_OP_TO_GFX_OP("overlay", OVERLAY)
+  else CANVAS_OP_TO_GFX_OP("darken", DARKEN)
+  else CANVAS_OP_TO_GFX_OP("lighten", LIGHTEN)
+  else CANVAS_OP_TO_GFX_OP("color-dodge", COLOR_DODGE)
+  else CANVAS_OP_TO_GFX_OP("color-burn", COLOR_BURN)
+  else CANVAS_OP_TO_GFX_OP("hard-light", HARD_LIGHT)
+  else CANVAS_OP_TO_GFX_OP("soft-light", SOFT_LIGHT)
+  else CANVAS_OP_TO_GFX_OP("difference", DIFFERENCE)
+  else CANVAS_OP_TO_GFX_OP("exclusion", EXCLUSION)
+  else CANVAS_OP_TO_GFX_OP("hue", HUE)
+  else CANVAS_OP_TO_GFX_OP("saturation", SATURATION)
+  else CANVAS_OP_TO_GFX_OP("color", COLOR)
+  else CANVAS_OP_TO_GFX_OP("luminosity", LUMINOSITY)
+  // XXX ERRMSG we need to report an error to developers here! (bug 329026)
+  else return;
+
+#undef CANVAS_OP_TO_GFX_OP
+  CurrentState().op = comp_op;
+}
+
+void
+BasicRenderingContext2D::GetGlobalCompositeOperation(nsAString& aOp,
+                                                     ErrorResult& aError)
+{
+  CompositionOp comp_op = CurrentState().op;
+
+#define CANVAS_OP_TO_GFX_OP(cvsop, op2d) \
+  if (comp_op == CompositionOp::OP_##op2d) \
+    aOp.AssignLiteral(cvsop);
+
+  CANVAS_OP_TO_GFX_OP("copy", SOURCE)
+  else CANVAS_OP_TO_GFX_OP("destination-atop", DEST_ATOP)
+  else CANVAS_OP_TO_GFX_OP("destination-in", DEST_IN)
+  else CANVAS_OP_TO_GFX_OP("destination-out", DEST_OUT)
+  else CANVAS_OP_TO_GFX_OP("destination-over", DEST_OVER)
+  else CANVAS_OP_TO_GFX_OP("lighter", ADD)
+  else CANVAS_OP_TO_GFX_OP("source-atop", ATOP)
+  else CANVAS_OP_TO_GFX_OP("source-in", IN)
+  else CANVAS_OP_TO_GFX_OP("source-out", OUT)
+  else CANVAS_OP_TO_GFX_OP("source-over", OVER)
+  else CANVAS_OP_TO_GFX_OP("xor", XOR)
+  else CANVAS_OP_TO_GFX_OP("multiply", MULTIPLY)
+  else CANVAS_OP_TO_GFX_OP("screen", SCREEN)
+  else CANVAS_OP_TO_GFX_OP("overlay", OVERLAY)
+  else CANVAS_OP_TO_GFX_OP("darken", DARKEN)
+  else CANVAS_OP_TO_GFX_OP("lighten", LIGHTEN)
+  else CANVAS_OP_TO_GFX_OP("color-dodge", COLOR_DODGE)
+  else CANVAS_OP_TO_GFX_OP("color-burn", COLOR_BURN)
+  else CANVAS_OP_TO_GFX_OP("hard-light", HARD_LIGHT)
+  else CANVAS_OP_TO_GFX_OP("soft-light", SOFT_LIGHT)
+  else CANVAS_OP_TO_GFX_OP("difference", DIFFERENCE)
+  else CANVAS_OP_TO_GFX_OP("exclusion", EXCLUSION)
+  else CANVAS_OP_TO_GFX_OP("hue", HUE)
+  else CANVAS_OP_TO_GFX_OP("saturation", SATURATION)
+  else CANVAS_OP_TO_GFX_OP("color", COLOR)
+  else CANVAS_OP_TO_GFX_OP("luminosity", LUMINOSITY)
+  else {
+    aError.Throw(NS_ERROR_FAILURE);
+  }
+
+#undef CANVAS_OP_TO_GFX_OP
+}
+
+//
 // path bits
 //
 void
 BasicRenderingContext2D::TransformWillUpdate()
 {
   EnsureTarget();
 
   // Store the matrix that would transform the current path to device

--- a/dom/canvas/BasicRenderingContext2D.h
+++ b/dom/canvas/BasicRenderingContext2D.h
@@ -2,20 +2,21 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef BasicRenderingContext2D_h
 #define BasicRenderingContext2D_h
 
 #include "FilterSupport.h"
 #include "mozilla/dom/CanvasRenderingContext2DBinding.h"
-#include "mozilla/gfx/Matrix.h"
+#include "mozilla/gfx/2D.h"
 #include "nsStyleStruct.h"
 #include "nsSVGEffects.h"
 
+using mozilla::gfx::CompositionOp;
 using mozilla::gfx::FilterDescription;
 using mozilla::gfx::Matrix;
 
 namespace mozilla {
 namespace dom {
 
 class HTMLImageElementOrHTMLCanvasElementOrHTMLVideoElementOrImageBitmap;
 typedef HTMLImageElementOrHTMLCanvasElementOrHTMLVideoElementOrImageBitmap
@@ -59,22 +60,34 @@ public:
                  double aDx, double aDy, mozilla::ErrorResult& aError);
   void SetTransform(double aM11, double aM12, double aM21, double aM22,
                     double aDx, double aDy, mozilla::ErrorResult& aError);
   void ResetTransform(mozilla::ErrorResult& aError);
 
   //
   // CanvasCompositing
   //
-  virtual double GlobalAlpha() = 0;
-  virtual void SetGlobalAlpha(double aGlobalAlpha) = 0;
-  virtual void GetGlobalCompositeOperation(nsAString& aOp,
-                                           mozilla::ErrorResult& aError) = 0;
-  virtual void SetGlobalCompositeOperation(const nsAString& aOp,
-                                           mozilla::ErrorResult& aError) = 0;
+  double GlobalAlpha()
+  {
+    return CurrentState().globalAlpha;
+  }
+
+  // Useful for silencing cast warnings
+  static mozilla::gfx::Float ToFloat(double aValue) { return mozilla::gfx::Float(aValue); }
+
+  void SetGlobalAlpha(double aGlobalAlpha)
+  {
+    if (aGlobalAlpha >= 0.0 && aGlobalAlpha <= 1.0) {
+      CurrentState().globalAlpha = ToFloat(aGlobalAlpha);
+    }
+  }
+  void GetGlobalCompositeOperation(nsAString& aOp,
+                                   mozilla::ErrorResult& aError);
+  void SetGlobalCompositeOperation(const nsAString& aOp,
+                                   mozilla::ErrorResult& aError);
 
   //
   // CanvasImageSmoothing
   //
   virtual bool ImageSmoothingEnabled() = 0;
   virtual void SetImageSmoothingEnabled(bool aImageSmoothingEnabled) = 0;
 
   //
@@ -250,17 +263,17 @@ protected:
   ContextState() : textAlign(TextAlign::START),
                    textBaseline(TextBaseline::ALPHABETIC),
                    shadowColor(0),
                    lineWidth(1.0f),
                    miterLimit(10.0f),
                    globalAlpha(1.0f),
                    shadowBlur(0.0),
                    dashOffset(0.0f),
-                   op(mozilla::gfx::CompositionOp::OP_OVER),
+                   op(CompositionOp::OP_OVER),
                    fillRule(mozilla::gfx::FillRule::FILL_WINDING),
                    lineCap(mozilla::gfx::CapStyle::BUTT),
                    lineJoin(mozilla::gfx::JoinStyle::MITER_OR_BEVEL),
                    filterString(u"none"),
                    filterSourceGraphicTainted(false),
                    imageSmoothingEnabled(true),
                    fontExplicitLanguage(false)
   { }
@@ -356,17 +369,17 @@ protected:
   mozilla::gfx::Point shadowOffset;
   mozilla::gfx::Float lineWidth;
   mozilla::gfx::Float miterLimit;
   mozilla::gfx::Float globalAlpha;
   mozilla::gfx::Float shadowBlur;
   nsTArray<mozilla::gfx::Float> dash;
   mozilla::gfx::Float dashOffset;
 
-  mozilla::gfx::CompositionOp op;
+  CompositionOp op;
   mozilla::gfx::FillRule fillRule;
   mozilla::gfx::CapStyle lineCap;
   mozilla::gfx::JoinStyle lineJoin;
 
   nsString filterString;
   nsTArray<nsStyleFilter> filterChain;
   RefPtr<nsSVGFilterChainObserver> filterChainObserver;
   mozilla::gfx::FilterDescription filter;

--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -4949,102 +4949,16 @@ CanvasRenderingContext2D::DrawDirectlyTo
          aImage.mWhichFrame, SamplingFilter::GOOD, Some(svgContext), modifiedFlags, 1.0);
 
   if (result != DrawResult::SUCCESS) {
     NS_WARNING("imgIContainer::Draw failed");
   }
 }
 
 void
-CanvasRenderingContext2D::SetGlobalCompositeOperation(const nsAString& aOp,
-                                                      ErrorResult& aError)
-{
-  CompositionOp comp_op;
-
-#define CANVAS_OP_TO_GFX_OP(cvsop, op2d) \
-  if (aOp.EqualsLiteral(cvsop))   \
-    comp_op = CompositionOp::OP_##op2d;
-
-  CANVAS_OP_TO_GFX_OP("copy", SOURCE)
-  else CANVAS_OP_TO_GFX_OP("source-atop", ATOP)
-  else CANVAS_OP_TO_GFX_OP("source-in", IN)
-  else CANVAS_OP_TO_GFX_OP("source-out", OUT)
-  else CANVAS_OP_TO_GFX_OP("source-over", OVER)
-  else CANVAS_OP_TO_GFX_OP("destination-in", DEST_IN)
-  else CANVAS_OP_TO_GFX_OP("destination-out", DEST_OUT)
-  else CANVAS_OP_TO_GFX_OP("destination-over", DEST_OVER)
-  else CANVAS_OP_TO_GFX_OP("destination-atop", DEST_ATOP)
-  else CANVAS_OP_TO_GFX_OP("lighter", ADD)
-  else CANVAS_OP_TO_GFX_OP("xor", XOR)
-  else CANVAS_OP_TO_GFX_OP("multiply", MULTIPLY)
-  else CANVAS_OP_TO_GFX_OP("screen", SCREEN)
-  else CANVAS_OP_TO_GFX_OP("overlay", OVERLAY)
-  else CANVAS_OP_TO_GFX_OP("darken", DARKEN)
-  else CANVAS_OP_TO_GFX_OP("lighten", LIGHTEN)
-  else CANVAS_OP_TO_GFX_OP("color-dodge", COLOR_DODGE)
-  else CANVAS_OP_TO_GFX_OP("color-burn", COLOR_BURN)
-  else CANVAS_OP_TO_GFX_OP("hard-light", HARD_LIGHT)
-  else CANVAS_OP_TO_GFX_OP("soft-light", SOFT_LIGHT)
-  else CANVAS_OP_TO_GFX_OP("difference", DIFFERENCE)
-  else CANVAS_OP_TO_GFX_OP("exclusion", EXCLUSION)
-  else CANVAS_OP_TO_GFX_OP("hue", HUE)
-  else CANVAS_OP_TO_GFX_OP("saturation", SATURATION)
-  else CANVAS_OP_TO_GFX_OP("color", COLOR)
-  else CANVAS_OP_TO_GFX_OP("luminosity", LUMINOSITY)
-  // XXX ERRMSG we need to report an error to developers here! (bug 329026)
-  else return;
-
-#undef CANVAS_OP_TO_GFX_OP
-  CurrentState().op = comp_op;
-}
-
-void
-CanvasRenderingContext2D::GetGlobalCompositeOperation(nsAString& aOp,
-                                                      ErrorResult& aError)
-{
-  CompositionOp comp_op = CurrentState().op;
-
-#define CANVAS_OP_TO_GFX_OP(cvsop, op2d) \
-  if (comp_op == CompositionOp::OP_##op2d) \
-    aOp.AssignLiteral(cvsop);
-
-  CANVAS_OP_TO_GFX_OP("copy", SOURCE)
-  else CANVAS_OP_TO_GFX_OP("destination-atop", DEST_ATOP)
-  else CANVAS_OP_TO_GFX_OP("destination-in", DEST_IN)
-  else CANVAS_OP_TO_GFX_OP("destination-out", DEST_OUT)
-  else CANVAS_OP_TO_GFX_OP("destination-over", DEST_OVER)
-  else CANVAS_OP_TO_GFX_OP("lighter", ADD)
-  else CANVAS_OP_TO_GFX_OP("source-atop", ATOP)
-  else CANVAS_OP_TO_GFX_OP("source-in", IN)
-  else CANVAS_OP_TO_GFX_OP("source-out", OUT)
-  else CANVAS_OP_TO_GFX_OP("source-over", OVER)
-  else CANVAS_OP_TO_GFX_OP("xor", XOR)
-  else CANVAS_OP_TO_GFX_OP("multiply", MULTIPLY)
-  else CANVAS_OP_TO_GFX_OP("screen", SCREEN)
-  else CANVAS_OP_TO_GFX_OP("overlay", OVERLAY)
-  else CANVAS_OP_TO_GFX_OP("darken", DARKEN)
-  else CANVAS_OP_TO_GFX_OP("lighten", LIGHTEN)
-  else CANVAS_OP_TO_GFX_OP("color-dodge", COLOR_DODGE)
-  else CANVAS_OP_TO_GFX_OP("color-burn", COLOR_BURN)
-  else CANVAS_OP_TO_GFX_OP("hard-light", HARD_LIGHT)
-  else CANVAS_OP_TO_GFX_OP("soft-light", SOFT_LIGHT)
-  else CANVAS_OP_TO_GFX_OP("difference", DIFFERENCE)
-  else CANVAS_OP_TO_GFX_OP("exclusion", EXCLUSION)
-  else CANVAS_OP_TO_GFX_OP("hue", HUE)
-  else CANVAS_OP_TO_GFX_OP("saturation", SATURATION)
-  else CANVAS_OP_TO_GFX_OP("color", COLOR)
-  else CANVAS_OP_TO_GFX_OP("luminosity", LUMINOSITY)
-  else {
-    aError.Throw(NS_ERROR_FAILURE);
-  }
-
-#undef CANVAS_OP_TO_GFX_OP
-}
-
-void
 CanvasRenderingContext2D::DrawWindow(nsGlobalWindow& aWindow, double aX,
                                      double aY, double aW, double aH,
                                      const nsAString& aBgColor,
                                      uint32_t aFlags, ErrorResult& aError)
 {
   MOZ_ASSERT(aWindow.IsInnerWindow());
 
   if (int32_t(aW) == 0 || int32_t(aH) == 0) {

--- a/dom/canvas/CanvasRenderingContext2D.h
+++ b/dom/canvas/CanvasRenderingContext2D.h
@@ -15,17 +15,16 @@
 #include "mozilla/dom/HTMLVideoElement.h"
 #include "gfxTextRun.h"
 #include "mozilla/ErrorResult.h"
 #include "mozilla/dom/BasicRenderingContext2D.h"
 #include "mozilla/dom/CanvasGradient.h"
 #include "mozilla/dom/CanvasRenderingContext2DBinding.h"
 #include "mozilla/dom/CanvasPattern.h"
 #include "mozilla/gfx/Rect.h"
-#include "mozilla/gfx/2D.h"
 #include "mozilla/UniquePtr.h"
 #include "gfx2DGlue.h"
 #include "imgIEncoder.h"
 #include "nsLayoutUtils.h"
 #include "mozilla/EnumeratedArray.h"
 #include "Layers.h"
 
 class nsGlobalWindow;
@@ -71,36 +70,16 @@ public:
     if (!mCanvasElement || mCanvasElement->IsInNativeAnonymousSubtree()) {
       return nullptr;
     }
 
     // corresponds to changes to the old bindings made in bug 745025
     return mCanvasElement->GetOriginalCanvas();
   }
 
-  double GlobalAlpha() override
-  {
-    return CurrentState().globalAlpha;
-  }
-
-  // Useful for silencing cast warnings
-  static mozilla::gfx::Float ToFloat(double aValue) { return mozilla::gfx::Float(aValue); }
-
-  void SetGlobalAlpha(double aGlobalAlpha) override
-  {
-    if (aGlobalAlpha >= 0.0 && aGlobalAlpha <= 1.0) {
-      CurrentState().globalAlpha = ToFloat(aGlobalAlpha);
-    }
-  }
-
-  void GetGlobalCompositeOperation(nsAString& aOp,
-                                   mozilla::ErrorResult& aError) override;
-  void SetGlobalCompositeOperation(const nsAString& aOp,
-                                   mozilla::ErrorResult& aError) override;
-
   void
   GetStrokeStyle(OwningStringOrCanvasGradientOrCanvasPattern& aValue) override
   {
     GetStyleAsUnion(aValue, Style::STROKE);
   }
 
   void
   SetStrokeStyle(const StringOrCanvasGradientOrCanvasPattern& aValue) override