cc: Add CopyResource function to ResourceProvider API.

cc/resources/image_raster_worker_pool.cc

 // Copyright 2013 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/image_raster_worker_pool.h"
 
 #include "base/debug/trace_event.h"
 #include "cc/debug/traced_value.h"
 #include "cc/resources/resource.h"
 
@@ skipping 133 matching lines @@
   }
   completed_tasks_.clear();
 }
 
 SkCanvas* ImageRasterWorkerPool::AcquireCanvasForRaster(RasterTask* task) {
   return resource_provider_->MapImageRasterBuffer(task->resource()->id());
 }
 
 void ImageRasterWorkerPool::ReleaseCanvasForRaster(RasterTask* task) {
   resource_provider_->UnmapImageRasterBuffer(task->resource()->id());
+
+  // Map/UnmapImageRasterBuffer provides direct access to the memory used by the
+  // GPU. Read lock fences are required to ensure that we're not trying to map a
+  // resource that is currently in-use by the GPU.
+  resource_provider_->EnableReadLockFences(task->resource()->id(), true);
 }
 
 void ImageRasterWorkerPool::OnRasterFinished() {
   TRACE_EVENT0("cc", "ImageRasterWorkerPool::OnRasterFinished");
 
   DCHECK(raster_tasks_pending_);
   raster_tasks_pending_ = false;
   TRACE_EVENT_ASYNC_END0("cc", "ScheduledTasks", this);
   client_->DidFinishRunningTasks();
 }
@@ skipping 16 matching lines @@
 
 scoped_ptr<base::Value> ImageRasterWorkerPool::StateAsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue);
 
   state->SetBoolean("tasks_required_for_activation_pending",
                     raster_tasks_required_for_activation_pending_);
   return state.PassAs<base::Value>();
 }
 
 }  // namespace cc