diff -r 000000000000 -r 6474c204b198 gfx/2d/DrawTargetDual.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/2d/DrawTargetDual.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,193 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+  * This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+     
+#include "DrawTargetDual.h"
+#include "Tools.h"
+
+namespace mozilla {
+namespace gfx {
+
+class DualSurface
+{
+public:
+  inline DualSurface(SourceSurface *aSurface)
+  {
+    if (aSurface->GetType() != SurfaceType::DUAL_DT) {
+      mA = mB = aSurface;
+      return;
+    }
+
+    SourceSurfaceDual *ssDual =
+      static_cast<SourceSurfaceDual*>(aSurface);
+    mA = ssDual->mA;
+    mB = ssDual->mB;
+  }
+
+  SourceSurface *mA;
+  SourceSurface *mB;
+};
+
+/* This only needs to split patterns up for SurfacePatterns. Only in that
+ * case can we be dealing with a 'dual' source (SourceSurfaceDual) and do
+ * we need to pass separate patterns into our destination DrawTargets.
+ */
+class DualPattern
+{
+public:
+  inline DualPattern(const Pattern &aPattern)
+    : mPatternsInitialized(false)
+  {
+    if (aPattern.GetType() != PatternType::SURFACE) {
+      mA = mB = &aPattern;
+      return;
+    }
+
+    const SurfacePattern *surfPat =
+      static_cast<const SurfacePattern*>(&aPattern);
+
+    if (surfPat->mSurface->GetType() != SurfaceType::DUAL_DT) {
+      mA = mB = &aPattern;
+      return;
+    }
+
+    const SourceSurfaceDual *ssDual =
+      static_cast<const SourceSurfaceDual*>(surfPat->mSurface.get());
+    mA = new (mSurfPatA.addr()) SurfacePattern(ssDual->mA, surfPat->mExtendMode,
+                                               surfPat->mMatrix, surfPat->mFilter);
+    mB = new (mSurfPatB.addr()) SurfacePattern(ssDual->mB, surfPat->mExtendMode,
+                                               surfPat->mMatrix, surfPat->mFilter);
+    mPatternsInitialized = true;
+  }
+
+  inline ~DualPattern()
+  {
+    if (mPatternsInitialized) {
+      mA->~Pattern();
+      mB->~Pattern();
+    }
+  }
+
+  ClassStorage<SurfacePattern> mSurfPatA;
+  ClassStorage<SurfacePattern> mSurfPatB;
+
+  const Pattern *mA;
+  const Pattern *mB;
+
+  bool mPatternsInitialized;
+};
+
+void
+DrawTargetDual::DrawSurface(SourceSurface *aSurface, const Rect &aDest, const Rect &aSource,
+                            const DrawSurfaceOptions &aSurfOptions, const DrawOptions &aOptions)
+{
+  DualSurface surface(aSurface);
+  mA->DrawSurface(surface.mA, aDest, aSource, aSurfOptions, aOptions);
+  mB->DrawSurface(surface.mB, aDest, aSource, aSurfOptions, aOptions);
+}
+
+void
+DrawTargetDual::DrawSurfaceWithShadow(SourceSurface *aSurface, const Point &aDest,
+                                      const Color &aColor, const Point &aOffset,
+                                      Float aSigma, CompositionOp aOp)
+{
+  DualSurface surface(aSurface);
+  mA->DrawSurfaceWithShadow(surface.mA, aDest, aColor, aOffset, aSigma, aOp);
+  mB->DrawSurfaceWithShadow(surface.mB, aDest, aColor, aOffset, aSigma, aOp);
+}
+
+void
+DrawTargetDual::MaskSurface(const Pattern &aSource,
+                           SourceSurface *aMask,
+                           Point aOffset,
+                           const DrawOptions &aOptions)
+{
+  DualPattern source(aSource);
+  DualSurface mask(aMask);
+  mA->MaskSurface(*source.mA, mask.mA, aOffset, aOptions);
+  mB->MaskSurface(*source.mB, mask.mB, aOffset, aOptions);
+}
+
+void
+DrawTargetDual::CopySurface(SourceSurface *aSurface, const IntRect &aSourceRect,
+                            const IntPoint &aDestination)
+{
+  DualSurface surface(aSurface);
+  mA->CopySurface(surface.mA, aSourceRect, aDestination);
+  mB->CopySurface(surface.mB, aSourceRect, aDestination);
+}
+
+void
+DrawTargetDual::FillRect(const Rect &aRect, const Pattern &aPattern, const DrawOptions &aOptions)
+{
+  DualPattern pattern(aPattern);
+  mA->FillRect(aRect, *pattern.mA, aOptions);
+  mB->FillRect(aRect, *pattern.mB, aOptions);
+}
+
+void
+DrawTargetDual::StrokeRect(const Rect &aRect, const Pattern &aPattern,
+                           const StrokeOptions &aStrokeOptions, const DrawOptions &aOptions)
+{
+  DualPattern pattern(aPattern);
+  mA->StrokeRect(aRect, *pattern.mA, aStrokeOptions, aOptions);
+  mB->StrokeRect(aRect, *pattern.mB, aStrokeOptions, aOptions);
+}
+
+void
+DrawTargetDual::StrokeLine(const Point &aStart, const Point &aEnd, const Pattern &aPattern,
+                           const StrokeOptions &aStrokeOptions, const DrawOptions &aOptions)
+{
+  DualPattern pattern(aPattern);
+  mA->StrokeLine(aStart, aEnd, *pattern.mA, aStrokeOptions, aOptions);
+  mB->StrokeLine(aStart, aEnd, *pattern.mB, aStrokeOptions, aOptions);
+}
+
+void
+DrawTargetDual::Stroke(const Path *aPath, const Pattern &aPattern,
+                       const StrokeOptions &aStrokeOptions, const DrawOptions &aOptions)
+{
+  DualPattern pattern(aPattern);
+  mA->Stroke(aPath, *pattern.mA, aStrokeOptions, aOptions);
+  mB->Stroke(aPath, *pattern.mB, aStrokeOptions, aOptions);
+}
+
+void
+DrawTargetDual::Fill(const Path *aPath, const Pattern &aPattern, const DrawOptions &aOptions)
+{
+  DualPattern pattern(aPattern);
+  mA->Fill(aPath, *pattern.mA, aOptions);
+  mB->Fill(aPath, *pattern.mB, aOptions);
+}
+
+void
+DrawTargetDual::FillGlyphs(ScaledFont *aScaledFont, const GlyphBuffer &aBuffer,
+                           const Pattern &aPattern, const DrawOptions &aOptions,
+                           const GlyphRenderingOptions *aRenderingOptions)
+{
+  DualPattern pattern(aPattern);
+  mA->FillGlyphs(aScaledFont, aBuffer, *pattern.mA, aOptions, aRenderingOptions);
+  mB->FillGlyphs(aScaledFont, aBuffer, *pattern.mB, aOptions, aRenderingOptions);
+}
+
+void
+DrawTargetDual::Mask(const Pattern &aSource, const Pattern &aMask, const DrawOptions &aOptions)
+{
+  DualPattern source(aSource);
+  DualPattern mask(aMask);
+  mA->Mask(*source.mA, *mask.mA, aOptions);
+  mB->Mask(*source.mB, *mask.mB, aOptions);
+}
+
+TemporaryRef<DrawTarget>
+DrawTargetDual::CreateSimilarDrawTarget(const IntSize &aSize, SurfaceFormat aFormat) const
+{
+  RefPtr<DrawTarget> dtA = mA->CreateSimilarDrawTarget(aSize, aFormat);
+  RefPtr<DrawTarget> dtB = mB->CreateSimilarDrawTarget(aSize, aFormat);
+
+  return new DrawTargetDual(dtA, dtB);
+}
+
+}
+}