content: Increase thread priority for display critical IO threads on ChromeOS.

content/gpu/in_process_gpu_thread.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 "content/gpu/in_process_gpu_thread.h"
 
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "content/common/gpu/gpu_memory_buffer_factory.h"
 #include "content/gpu/gpu_child_thread.h"
@@ skipping 29 matching lines @@
 
 void InProcessGpuThread::Init() {
   // Call AttachCurrentThreadWithName, before any other AttachCurrentThread()
   // calls. The latter causes Java VM to assign Thread-??? to the thread name.
   // Please note calls to AttachCurrentThreadWithName after AttachCurrentThread
   // will not change the thread name kept in Java VM.
 #if defined(OS_ANDROID)
   base::android::AttachCurrentThreadWithName(thread_name());
 #endif
 
-  gpu_process_ = new GpuProcess();
+  gpu_process_ = new GpuProcess(base::ThreadPriority::NORMAL);

[piman, 2016/02/12 21:09:14]

Android uses this, and it would make sense to bump to DISPLAY too. If I follow
the code correctly, it is done in ChildProcess, but it could make sense to do it
explicitly here (and maybe eventually remove from ChildProcess, since it may not
make sense for e.g. the utility process, and arguable on the renderer).

[reveman, 2016/02/12 21:40:21]

Makes sense. Latest patch sets the priority here and I added a TODO for removing
it from ChildProcess ctor. I'd rather not change the priority of any threads on
Android as part of this patch.

FYI, we increase the priority of the compositor thread in the renderer on
Android. Not sure that's a good idea but it makes sense to also increase the
priority of the IO thread when we do that.

 
   // The process object takes ownership of the thread object, so do not
   // save and delete the pointer.
   GpuChildThread* child_thread = new GpuChildThread(
       params_, gpu_memory_buffer_factory_.get(), sync_point_manager_override_);
 
   // Since we are in the browser process, use the thread start time as the
   // process start time.
   child_thread->Init(base::Time::Now());
 
   gpu_process_->set_main_thread(child_thread);
 }
 
 void InProcessGpuThread::CleanUp() {
   SetThreadWasQuitProperly(true);
   delete gpu_process_;
 }
 
 base::Thread* CreateInProcessGpuThread(
     const InProcessChildThreadParams& params) {
   return new InProcessGpuThread(params, nullptr);
 }
 
 }  // namespace content