diff -r 000000000000 -r 6474c204b198 gfx/layers/basic/BasicLayersImpl.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/layers/basic/BasicLayersImpl.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,195 @@
+/* -*- Mode: C++; tab-width: 2; 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 "BasicLayersImpl.h"
+#include <new>                          // for operator new
+#include "Layers.h"                     // for Layer, etc
+#include "basic/BasicImplData.h"        // for BasicImplData
+#include "mozilla/Assertions.h"         // for MOZ_ASSERT, etc
+#include "mozilla/DebugOnly.h"          // for DebugOnly
+#include "mozilla/layers/CompositorTypes.h"
+#include "mozilla/layers/ISurfaceAllocator.h"
+#include "AutoMaskData.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace layers {
+
+bool
+GetMaskData(Layer* aMaskLayer,
+            const Point& aDeviceOffset,
+            AutoMoz2DMaskData* aMaskData)
+{
+  if (aMaskLayer) {
+    RefPtr<SourceSurface> surface =
+      static_cast<BasicImplData*>(aMaskLayer->ImplData())->GetAsSourceSurface();
+    if (surface) {
+      Matrix transform;
+      Matrix4x4 effectiveTransform = aMaskLayer->GetEffectiveTransform();
+      DebugOnly<bool> maskIs2D = effectiveTransform.CanDraw2D(&transform);
+      NS_ASSERTION(maskIs2D, "How did we end up with a 3D transform here?!");
+      transform.Translate(-aDeviceOffset.x, -aDeviceOffset.y);
+      aMaskData->Construct(transform, surface);
+      return true;
+    }
+  }
+  return false;
+}
+
+void
+PaintWithMask(gfxContext* aContext, float aOpacity, Layer* aMaskLayer)
+{
+  AutoMoz2DMaskData mask;
+  if (GetMaskData(aMaskLayer, Point(), &mask)) {
+    if (aOpacity < 1.0) {
+      aContext->PushGroup(gfxContentType::COLOR_ALPHA);
+      aContext->Paint(aOpacity);
+      aContext->PopGroupToSource();
+    }
+    aContext->SetMatrix(ThebesMatrix(mask.GetTransform()));
+    aContext->Mask(mask.GetSurface());
+    return;
+  }
+
+  // if there is no mask, just paint normally
+  aContext->Paint(aOpacity);
+}
+
+void
+FillRectWithMask(DrawTarget* aDT,
+                 const Rect& aRect,
+                 const Color& aColor,
+                 const DrawOptions& aOptions,
+                 SourceSurface* aMaskSource,
+                 const Matrix* aMaskTransform)
+{
+  if (aMaskSource && aMaskTransform) {
+    aDT->PushClipRect(aRect);
+    Matrix oldTransform = aDT->GetTransform();
+
+    aDT->SetTransform(*aMaskTransform);
+    aDT->MaskSurface(ColorPattern(aColor), aMaskSource, Point(), aOptions);
+    aDT->SetTransform(oldTransform);
+    aDT->PopClip();
+    return;
+  }
+
+  aDT->FillRect(aRect, ColorPattern(aColor), aOptions);
+}
+void
+FillRectWithMask(DrawTarget* aDT,
+                 const gfx::Point& aDeviceOffset,
+                 const Rect& aRect,
+                 const Color& aColor,
+                 const DrawOptions& aOptions,
+                 Layer* aMaskLayer)
+{
+  AutoMoz2DMaskData mask;
+  if (GetMaskData(aMaskLayer, aDeviceOffset, &mask)) {
+    const Matrix& maskTransform = mask.GetTransform();
+    FillRectWithMask(aDT, aRect, aColor, aOptions, mask.GetSurface(), &maskTransform);
+    return;
+  }
+
+  FillRectWithMask(aDT, aRect, aColor, aOptions);
+}
+
+void
+FillRectWithMask(DrawTarget* aDT,
+                 const Rect& aRect,
+                 SourceSurface* aSurface,
+                 Filter aFilter,
+                 const DrawOptions& aOptions,
+                 ExtendMode aExtendMode,
+                 SourceSurface* aMaskSource,
+                 const Matrix* aMaskTransform,
+                 const Matrix* aSurfaceTransform)
+{
+  if (aMaskSource && aMaskTransform) {
+    aDT->PushClipRect(aRect);
+    Matrix oldTransform = aDT->GetTransform();
+
+    Matrix inverseMask = *aMaskTransform;
+    inverseMask.Invert();
+
+    Matrix transform = oldTransform * inverseMask;
+    if (aSurfaceTransform) {
+      transform = (*aSurfaceTransform) * transform;
+    }
+
+    SurfacePattern source(aSurface, aExtendMode, transform, aFilter);
+
+    aDT->SetTransform(*aMaskTransform);
+    aDT->MaskSurface(source, aMaskSource, Point(0, 0), aOptions);
+    aDT->SetTransform(oldTransform);
+    aDT->PopClip();
+    return;
+  }
+
+  aDT->FillRect(aRect,
+                SurfacePattern(aSurface, aExtendMode,
+                               aSurfaceTransform ? (*aSurfaceTransform) : Matrix(),
+                               aFilter), aOptions);
+}
+
+void
+FillRectWithMask(DrawTarget* aDT,
+                 const gfx::Point& aDeviceOffset,
+                 const Rect& aRect,
+                 SourceSurface* aSurface,
+                 Filter aFilter,
+                 const DrawOptions& aOptions,
+                 Layer* aMaskLayer)
+{
+  AutoMoz2DMaskData mask;
+  if (GetMaskData(aMaskLayer, aDeviceOffset, &mask)) {
+    const Matrix& maskTransform = mask.GetTransform();
+    FillRectWithMask(aDT, aRect, aSurface, aFilter, aOptions, ExtendMode::CLAMP,
+                     mask.GetSurface(), &maskTransform);
+    return;
+  }
+
+  FillRectWithMask(aDT, aRect, aSurface, aFilter, aOptions, ExtendMode::CLAMP);
+}
+
+BasicImplData*
+ToData(Layer* aLayer)
+{
+  return static_cast<BasicImplData*>(aLayer->ImplData());
+}
+
+gfx::CompositionOp
+GetEffectiveOperator(Layer* aLayer)
+{
+  CompositionOp op = aLayer->GetEffectiveMixBlendMode();
+
+  if (op != CompositionOp::OP_OVER) {
+    return op;
+  }
+
+  return ToData(aLayer)->GetOperator();
+}
+
+ShadowableLayer*
+ToShadowable(Layer* aLayer)
+{
+  return aLayer->AsShadowableLayer();
+}
+
+bool
+ShouldShadow(Layer* aLayer)
+{
+  if (!ToShadowable(aLayer)) {
+    NS_ABORT_IF_FALSE(aLayer->GetType() == Layer::TYPE_READBACK,
+                      "Only expect not to shadow ReadbackLayers");
+    return false;
+  }
+  return true;
+}
+
+
+}
+}