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

content/child/child_process.cc

 // Copyright (c) 2012 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/child/child_process.h"
 
 #include <string.h>
 
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 16 matching lines @@
 #endif
 
 namespace content {
 
 namespace {
 
 base::LazyInstance<base::ThreadLocalPointer<ChildProcess> > g_lazy_tls =
     LAZY_INSTANCE_INITIALIZER;
 }
 
-ChildProcess::ChildProcess()
+ChildProcess::ChildProcess() : ChildProcess(base::ThreadPriority::NORMAL) {}
+
+ChildProcess::ChildProcess(base::ThreadPriority io_thread_priority)
     : ref_count_(0),
       shutdown_event_(true, false),
       io_thread_("Chrome_ChildIOThread") {
   DCHECK(!g_lazy_tls.Pointer()->Get());
   g_lazy_tls.Pointer()->Set(this);
 
   base::StatisticsRecorder::Initialize();
 
   // We can't recover from failing to start the IO thread.
   base::Thread::Options thread_options(base::MessageLoop::TYPE_IO, 0);
+  thread_options.priority = io_thread_priority;
 #if defined(OS_ANDROID)
   thread_options.priority = base::ThreadPriority::DISPLAY;
 #endif
   CHECK(io_thread_.StartWithOptions(thread_options));
 }
 
 ChildProcess::~ChildProcess() {
   DCHECK(g_lazy_tls.Pointer()->Get() == this);
 
   // Signal this event before destroying the child process.  That way all
@@ skipping 80 matching lines @@
   memset(&sa, 0, sizeof(sa));
   sa.sa_handler = SigUSR1Handler;
   sigaction(SIGUSR1, &sa, NULL);
 
   pause();
 #endif  // defined(OS_ANDROID)
 #endif  // defined(OS_POSIX)
 }
 
 }  // namespace content