cc: Async readback.

cc/layers/layer.h

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYERS_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <string>
 #include <vector>
 
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/animation/layer_animation_value_observer.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/region.h"
 #include "cc/layers/draw_properties.h"
 #include "cc/layers/layer_lists.h"
 #include "cc/layers/layer_position_constraint.h"
 #include "cc/layers/paint_properties.h"
@@ skipping 48 matching lines @@
   void AddChild(scoped_refptr<Layer> child);
   void InsertChild(scoped_refptr<Layer> child, size_t index);
   void ReplaceChild(Layer* reference, scoped_refptr<Layer> new_layer);
   void RemoveFromParent();
   void RemoveAllChildren();
   void SetChildren(const LayerList& children);
 
   const LayerList& children() const { return children_; }
   Layer* child_at(size_t index) { return children_[index].get(); }
 
+  typedef base::Callback<void(scoped_ptr<SkBitmap>)>
+      RequestCopyAsBitmapCallback;
+
+  // This requests the layer and its subtree be rendered into an SkBitmap and
+  // call the given callback when the SkBitmap has been produced. If the copy
+  // is unable to be produced (the layer is destroyed first), then the callback
+  // is called with a NULL bitmap.
+  void RequestCopyAsBitmap(RequestCopyAsBitmapCallback callback);
+  bool HasRequestCopyCallback() const {
+    return !request_copy_callbacks_.empty();
+  }
+
   void SetAnchorPoint(gfx::PointF anchor_point);
   gfx::PointF anchor_point() const { return anchor_point_; }
 
   void SetAnchorPointZ(float anchor_point_z);
   float anchor_point_z() const { return anchor_point_z_; }
 
   virtual void SetBackgroundColor(SkColor background_color);
   SkColor background_color() const { return background_color_; }
 
   // A layer's bounds are in logical, non-page-scaled pixels (however, the
@@ skipping 384 matching lines @@
   // Replica layer used for reflections.
   scoped_refptr<Layer> replica_layer_;
 
   // Transient properties.
   float raster_scale_;
   bool automatically_compute_raster_scale_;
   bool bounds_contain_page_scale_;
 
   gfx::Transform impl_transform_;
 
+  std::vector<RequestCopyAsBitmapCallback> request_copy_callbacks_;
+
   WebKit::WebLayerScrollClient* layer_scroll_client_;
 
   DrawProperties<Layer, RenderSurface> draw_properties_;
 
   PaintProperties paint_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_