content: Implement dynamic priorities for raster threads.

cc/raster/single_thread_task_graph_runner.cc

 // Copyright 2015 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/raster/single_thread_task_graph_runner.h"
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/threading/simple_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/trace_event/trace_event.h"
 
 namespace cc {
 
 SingleThreadTaskGraphRunner::SingleThreadTaskGraphRunner()
     : lock_(),
+      work_queue_(this),
       has_ready_to_run_tasks_cv_(&lock_),
       has_namespaces_with_finished_running_tasks_cv_(&lock_),
       shutdown_(false) {}
 
 SingleThreadTaskGraphRunner::~SingleThreadTaskGraphRunner() {}
 
 void SingleThreadTaskGraphRunner::Start(
     const std::string& thread_name,
     const base::SimpleThread::Options& thread_options) {
   thread_.reset(
@@ skipping 134 matching lines @@
 
   // If namespace has finished running all tasks, wake up origin thread.
   if (work_queue_.HasFinishedRunningTasksInNamespace(
           prioritized_task.task_namespace))
     has_namespaces_with_finished_running_tasks_cv_.Signal();
 
   return true;
 }
 
 }  // namespace cc