content: Implement dynamic priorities for raster threads.

content/renderer/raster_worker_pool.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 "content/renderer/raster_worker_pool.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 137 matching lines @@
   std::vector<cc::TaskCategory> background_categories;
   background_categories.push_back(cc::TASK_CATEGORY_BACKGROUND);
 
   // Use background priority for background thread.
   base::SimpleThread::Options thread_options;
 #if !defined(OS_MACOSX)
   thread_options.set_priority(base::ThreadPriority::BACKGROUND);
 #endif
 
   scoped_ptr<base::SimpleThread> thread(new RasterWorkerPoolThread(
-      base::StringPrintf("CompositorTileWorker%u",
-                         static_cast<unsigned>(threads_.size() + 1))
-          .c_str(),
-      thread_options, this, background_categories,
-      &has_ready_to_run_background_tasks_cv_));
+      "CompositorTileWorkerBackground", thread_options, this,
+      background_categories, &has_ready_to_run_background_tasks_cv_));
   thread->Start();
   threads_.push_back(std::move(thread));
 }
 
 void RasterWorkerPool::Shutdown() {
   WaitForTasksToFinishRunning(namespace_token_);
   CollectCompletedTasks(namespace_token_, &completed_tasks_);
   // Shutdown raster threads.
   {
     base::AutoLock lock(lock_);
@@ skipping 254 matching lines @@
 
 // Overridden from cc::Task:
 void RasterWorkerPool::ClosureTask::RunOnWorkerThread() {
   closure_.Run();
   closure_.Reset();
 }
 
 RasterWorkerPool::ClosureTask::~ClosureTask() {}
 
 }  // namespace content