Support single-threaded impl-side painting

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 269 matching lines @@
   // Schedule new tasks.
   ScheduleMoreTasks();
 
   // Reschedule check for completed raster tasks.
   check_for_completed_raster_task_notifier_.Schedule();
 
   TRACE_EVENT_ASYNC_STEP_INTO1(
       "cc", "ScheduledTasks", this, StateName(), "state", StateAsValue());
 }
 
+void PixelBufferRasterWorkerPool::WaitForTasksToFinishRunning() {
+  task_graph_runner_->WaitForTasksToFinishRunning(namespace_token_);

[reveman, 2014/10/27 19:15:49]

Note that this doesn't do what is expected. It will only wait for currently
scheduled tasks to finish running and not take throttling into account.

+}
+
 void PixelBufferRasterWorkerPool::CheckForCompletedTasks() {
   TRACE_EVENT0("cc", "PixelBufferRasterWorkerPool::CheckForCompletedTasks");
 
   CheckForCompletedRasterizerTasks();
   CheckForCompletedUploads();
   FlushUploads();
 
   for (RasterizerTask::Vector::const_iterator it =
            completed_image_decode_tasks_.begin();
        it != completed_image_decode_tasks_.end();
@@ skipping 446 matching lines @@
 void PixelBufferRasterWorkerPool::ThrottleStateAsValueInto(
     base::debug::TracedValue* throttle_state) const {
   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_);
 }
 
 }  // namespace cc