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

content/gpu/in_process_gpu_thread.cc

Index: content/gpu/in_process_gpu_thread.cc
diff --git a/content/gpu/in_process_gpu_thread.cc b/content/gpu/in_process_gpu_thread.cc
index 59a4f487e599f8949861d7322b21f49002c405de..b1e53ec90ad2d5b68a158ef91143622da8701464 100644
--- a/content/gpu/in_process_gpu_thread.cc
+++ b/content/gpu/in_process_gpu_thread.cc
@@ -47,7 +47,7 @@ void InProcessGpuThread::Init() {
   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.