content: Improve thread priority 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 106 matching lines @@
   cc::Task::Vector completed_tasks_;
 };
 
 RasterWorkerPool::RasterWorkerPool()
     : namespace_token_(GetNamespaceToken()),
       has_ready_to_run_foreground_tasks_cv_(&lock_),
       has_ready_to_run_background_tasks_cv_(&lock_),
       has_namespaces_with_finished_running_tasks_cv_(&lock_),
       shutdown_(false) {}
 
-void RasterWorkerPool::Start(
-    int num_threads,
-    const base::SimpleThread::Options& thread_options) {
+void RasterWorkerPool::Start(int num_threads) {
   DCHECK(threads_.empty());
 
   // Start |num_threads| threads for foreground work, including nonconcurrent
   // foreground work.
   std::vector<cc::TaskCategory> foreground_categories;
   foreground_categories.push_back(cc::TASK_CATEGORY_NONCONCURRENT_FOREGROUND);
   foreground_categories.push_back(cc::TASK_CATEGORY_FOREGROUND);
 
   for (int i = 0; i < num_threads; i++) {
     scoped_ptr<base::SimpleThread> thread(new RasterWorkerPoolThread(
         base::StringPrintf("CompositorTileWorker%u",
                            static_cast<unsigned>(threads_.size() + 1))
             .c_str(),
-        thread_options, this, foreground_categories,
+        base::SimpleThread::Options(), this, foreground_categories,
         &has_ready_to_run_foreground_tasks_cv_));
     thread->Start();
     threads_.push_back(std::move(thread));
   }
 
   // Start a single thread for background work.
   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_));
   thread->Start();
   threads_.push_back(std::move(thread));
 }
 
@@ skipping 260 matching lines @@
 
 // Overridden from cc::Task:
 void RasterWorkerPool::ClosureTask::RunOnWorkerThread() {
   closure_.Run();
   closure_.Reset();
 }
 
 RasterWorkerPool::ClosureTask::~ClosureTask() {}
 
 }  // namespace content