cc: Add CopyResource function to ResourceProvider API.

cc/resources/pixel_buffer_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/pixel_buffer_raster_worker_pool.h"
 
 #include <algorithm>
 
 #include "base/containers/stack_container.h"
 #include "base/debug/trace_event.h"
@@ skipping 383 matching lines @@
                      RasterTaskState::TaskComparator(task));
     DCHECK(state_it != raster_task_states_.end());
     RasterTaskState& state = *state_it;
 
     bytes_pending_upload_ -= task->resource()->bytes();
 
     task->WillComplete();
     task->CompleteOnOriginThread(this);
     task->DidComplete();
 
+    // Async set pixels commands are not necessarily processed in-sequence with
+    // drawing commands. Read lock fences are required to ensure that async
+    // commands don't access the resource while used for drawing.
+    resource_provider_->EnableReadLockFences(task->resource()->id(), true);
+
     DCHECK(std::find(completed_raster_tasks_.begin(),
                      completed_raster_tasks_.end(),
                      task) == completed_raster_tasks_.end());
     completed_raster_tasks_.push_back(task);
     state.type = RasterTaskState::COMPLETED;
     DCHECK_LE(static_cast<size_t>(state.required_for_activation),
               raster_tasks_required_for_activation_count_);
     raster_tasks_required_for_activation_count_ -=
         state.required_for_activation;
   }
@@ skipping 373 matching lines @@
 
   throttle_state->SetInteger("bytes_available_for_upload",
                              max_bytes_pending_upload_ - bytes_pending_upload_);
   throttle_state->SetInteger("bytes_pending_upload", bytes_pending_upload_);
   throttle_state->SetInteger("scheduled_raster_task_count",
                              scheduled_raster_task_count_);
   return throttle_state.PassAs<base::Value>();
 }
 
 }  // namespace cc