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diff --git a/gfx/layers/basic/BasicLayers.h b/gfx/layers/basic/BasicLayers.h
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+++ b/gfx/layers/basic/BasicLayers.h
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+/* -*- 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/. */
+
+#ifndef GFX_BASICLAYERS_H
+#define GFX_BASICLAYERS_H
+
+#include <stdint.h>                     // for INT32_MAX, int32_t
+#include "Layers.h"                     // for Layer (ptr only), etc
+#include "gfxTypes.h"
+#include "gfxContext.h"                 // for gfxContext
+#include "mozilla/Attributes.h"         // for override
+#include "mozilla/WidgetUtils.h"        // for ScreenRotation
+#include "mozilla/layers/LayersTypes.h"  // for BufferMode, LayersBackend, etc
+#include "nsAString.h"
+#include "nsCOMPtr.h"                   // for already_AddRefed
+#include "nsISupportsImpl.h"            // for gfxContext::AddRef, etc
+#include "nsRegion.h"                   // for nsIntRegion
+#include "nscore.h"                     // for nsAString, etc
+
+class nsIWidget;
+
+namespace mozilla {
+namespace layers {
+
+class ImageFactory;
+class ImageLayer;
+class PaintLayerContext;
+class ReadbackLayer;
+
+/**
+ * This is a cairo/Thebes-only, main-thread-only implementation of layers.
+ * 
+ * In each transaction, the client sets up the layer tree and then during
+ * the drawing phase, each PaintedLayer is painted directly into the target
+ * context (with appropriate clipping and Push/PopGroups performed
+ * between layers).
+ */
+class BasicLayerManager final :
+    public LayerManager
+{
+public:
+  enum BasicLayerManagerType {
+    BLM_WIDGET,
+    BLM_OFFSCREEN,
+    BLM_INACTIVE
+  };
+  /**
+   * Construct a BasicLayerManager which will have no default
+   * target context. SetDefaultTarget or BeginTransactionWithTarget
+   * must be called for any rendering to happen. PaintedLayers will not
+   * be retained.
+   */
+  explicit BasicLayerManager(BasicLayerManagerType aType);
+  /**
+   * Construct a BasicLayerManager which will have no default
+   * target context. SetDefaultTarget or BeginTransactionWithTarget
+   * must be called for any rendering to happen. PaintedLayers will be
+   * retained; that is, we will try to retain the visible contents of
+   * PaintedLayers as cairo surfaces. We create PaintedLayer buffers by
+   * creating similar surfaces to the default target context, or to
+   * aWidget's GetThebesSurface if there is no default target context, or
+   * to the passed-in context if there is no widget and no default
+   * target context.
+   * 
+   * This does not keep a strong reference to the widget, so the caller
+   * must ensure that the widget outlives the layer manager or call
+   * ClearWidget before the widget dies.
+   */
+  explicit BasicLayerManager(nsIWidget* aWidget);
+
+protected:
+  virtual ~BasicLayerManager();
+
+public:
+  BasicLayerManager* AsBasicLayerManager() override { return this; }
+
+  /**
+   * Set the default target context that will be used when BeginTransaction
+   * is called. This can only be called outside a transaction.
+   * 
+   * aDoubleBuffering can request double-buffering for drawing to the
+   * default target. When BUFFERED, the layer manager avoids blitting
+   * temporary results to aContext and then overpainting them with final
+   * results, by using a temporary buffer when necessary. In BUFFERED
+   * mode we always completely overwrite the contents of aContext's
+   * destination surface (within the clip region) using OP_SOURCE.
+   */
+  void SetDefaultTarget(gfxContext* aContext);
+  virtual void SetDefaultTargetConfiguration(BufferMode aDoubleBuffering, ScreenRotation aRotation);
+  gfxContext* GetDefaultTarget() { return mDefaultTarget; }
+
+  nsIWidget* GetRetainerWidget() { return mWidget; }
+  void ClearRetainerWidget() { mWidget = nullptr; }
+
+  virtual bool IsWidgetLayerManager() override { return mWidget != nullptr; }
+  virtual bool IsInactiveLayerManager() override { return mType == BLM_INACTIVE; }
+
+  virtual bool BeginTransaction() override;
+  virtual bool BeginTransactionWithTarget(gfxContext* aTarget) override;
+  virtual bool EndEmptyTransaction(EndTransactionFlags aFlags = END_DEFAULT) override;
+  virtual void EndTransaction(DrawPaintedLayerCallback aCallback,
+                              void* aCallbackData,
+                              EndTransactionFlags aFlags = END_DEFAULT) override;
+  virtual bool ShouldAvoidComponentAlphaLayers() override { return IsWidgetLayerManager(); }
+
+  void AbortTransaction();
+
+  virtual void SetRoot(Layer* aLayer) override;
+
+  virtual already_AddRefed<PaintedLayer> CreatePaintedLayer() override;
+  virtual already_AddRefed<ContainerLayer> CreateContainerLayer() override;
+  virtual already_AddRefed<ImageLayer> CreateImageLayer() override;
+  virtual already_AddRefed<CanvasLayer> CreateCanvasLayer() override;
+  virtual already_AddRefed<ColorLayer> CreateColorLayer() override;
+  virtual already_AddRefed<ReadbackLayer> CreateReadbackLayer() override;
+  virtual ImageFactory *GetImageFactory();
+
+  virtual LayersBackend GetBackendType() override { return LayersBackend::LAYERS_BASIC; }
+  virtual void GetBackendName(nsAString& name) override { name.AssignLiteral("Basic"); }
+
+  bool InConstruction() { return mPhase == PHASE_CONSTRUCTION; }
+#ifdef DEBUG
+  bool InDrawing() { return mPhase == PHASE_DRAWING; }
+  bool InForward() { return mPhase == PHASE_FORWARD; }
+#endif
+  bool InTransaction() { return mPhase != PHASE_NONE; }
+
+  gfxContext* GetTarget() { return mTarget; }
+  void SetTarget(gfxContext* aTarget) { mUsingDefaultTarget = false; mTarget = aTarget; }
+  bool IsRetained() { return mWidget != nullptr; }
+
+  virtual const char* Name() const override { return "Basic"; }
+
+  // Clear the cached contents of this layer tree.
+  virtual void ClearCachedResources(Layer* aSubtree = nullptr) override;
+
+  void SetTransactionIncomplete() { mTransactionIncomplete = true; }
+  bool IsTransactionIncomplete() { return mTransactionIncomplete; }
+
+  struct PushedGroup
+  {
+    PushedGroup() : mFinalTarget(nullptr), mNeedsClipToVisibleRegion(false), mOperator(gfx::CompositionOp::OP_COUNT), mOpacity(0.0f){}
+    gfxContext* mFinalTarget;
+    RefPtr<gfxContext> mGroupTarget;
+    nsIntRegion mVisibleRegion;
+    bool mNeedsClipToVisibleRegion;
+    gfx::IntPoint mGroupOffset;
+    gfx::CompositionOp mOperator;
+    gfx::Float mOpacity;
+    RefPtr<gfx::SourceSurface> mMaskSurface;
+    gfx::Matrix mMaskTransform;
+  };
+
+  // Construct a PushedGroup for a specific layer.
+  // Return false if it has some errors in PushGroupForLayer(). Then, the
+  // "aGroupResult" is unavailable for future using.
+  bool PushGroupForLayer(gfxContext* aContext, Layer* aLayerContext, const nsIntRegion& aRegion, PushedGroup& aGroupResult);
+
+  void PopGroupForLayer(PushedGroup& aGroup);
+
+  virtual bool IsCompositingCheap() override { return false; }
+  virtual int32_t GetMaxTextureSize() const override { return INT32_MAX; }
+  bool CompositorMightResample() { return mCompositorMightResample; }
+
+protected:
+  enum TransactionPhase {
+    PHASE_NONE, PHASE_CONSTRUCTION, PHASE_DRAWING, PHASE_FORWARD
+  };
+  TransactionPhase mPhase;
+
+  // This is the main body of the PaintLayer routine which will if it has
+  // children, recurse into PaintLayer() otherwise it will paint using the
+  // underlying Paint() method of the Layer. It will not do both.
+  void PaintSelfOrChildren(PaintLayerContext& aPaintContext, gfxContext* aGroupTarget);
+
+  // Paint the group onto the underlying target. This is used by PaintLayer to
+  // flush the group to the underlying target.
+  void FlushGroup(PaintLayerContext& aPaintContext, bool aNeedsClipToVisibleRegion);
+
+  // Paints aLayer to mTarget.
+  void PaintLayer(gfxContext* aTarget,
+                  Layer* aLayer,
+                  DrawPaintedLayerCallback aCallback,
+                  void* aCallbackData);
+
+  // Clear the contents of a layer
+  void ClearLayer(Layer* aLayer);
+
+  bool EndTransactionInternal(DrawPaintedLayerCallback aCallback,
+                              void* aCallbackData,
+                              EndTransactionFlags aFlags = END_DEFAULT);
+
+  void FlashWidgetUpdateArea(gfxContext* aContext);
+
+  // Widget whose surface should be used as the basis for PaintedLayer
+  // buffers.
+  nsIWidget* mWidget;
+  // The default context for BeginTransaction.
+  RefPtr<gfxContext> mDefaultTarget;
+  // The context to draw into.
+  RefPtr<gfxContext> mTarget;
+  // Image factory we use.
+  RefPtr<ImageFactory> mFactory;
+
+  BufferMode mDoubleBuffering;
+  BasicLayerManagerType mType;
+  bool mUsingDefaultTarget;
+  bool mTransactionIncomplete;
+  bool mCompositorMightResample;
+};
+
+} // namespace layers
+} // namespace mozilla
+
+#endif /* GFX_BASICLAYERS_H */