cc: Do bitmap conversion for RasterBuffer in the worker thread.

cc/resources/rasterizer.cc

 // Copyright 2014 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.
 
 #include "cc/resources/rasterizer.h"
 
 #include <algorithm>
 
 namespace cc {
 
@@ skipping 30 matching lines @@
 bool RasterizerTask::HasCompleted() const { return did_complete_; }
 
 ImageDecodeTask::ImageDecodeTask() {}
 
 ImageDecodeTask::~ImageDecodeTask() {}
 
 ImageDecodeTask* ImageDecodeTask::AsImageDecodeTask() { return this; }
 
 RasterTask::RasterTask(const Resource* resource,
                        ImageDecodeTask::Vector* dependencies)
-    : resource_(resource) {
+    : resource_(resource), content_has_changed_(false) {
   dependencies_.swap(*dependencies);
 }
 
 RasterTask::~RasterTask() {}
 
 RasterTask* RasterTask::AsRasterTask() { return this; }
 
+void RasterTask::set_content_has_changed(bool content_has_changed) {
+  content_has_changed_ = content_has_changed;
+}
+
 RasterTaskQueue::Item::Item(RasterTask* task, bool required_for_activation)
     : task(task), required_for_activation(required_for_activation) {}
 
 RasterTaskQueue::Item::~Item() {}
 
 RasterTaskQueue::RasterTaskQueue() : required_for_activation_count(0u) {}
 
 RasterTaskQueue::~RasterTaskQueue() {}
 
 void RasterTaskQueue::Swap(RasterTaskQueue* other) {
   items.swap(other->items);
   std::swap(required_for_activation_count,
             other->required_for_activation_count);
 }
 
 void RasterTaskQueue::Reset() {
   required_for_activation_count = 0u;
   items.clear();
 }
 
 }  // namespace cc