Turn ThreadPriority enum into an enum class.

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"
 
 #if defined(OS_POSIX) && !defined(OS_ANDROID)
 #include <signal.h>  // For SigUSR1Handler below.
 #endif
 
@@ skipping 30 matching lines @@
   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.
   CHECK(io_thread_.StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0)));
 
 #if defined(OS_ANDROID)
-  io_thread_.SetPriority(base::kThreadPriority_Display);
+  io_thread_.SetPriority(base::ThreadPriority::DISPLAY);
 #endif
 }
 
 ChildProcess::~ChildProcess() {
   DCHECK(g_lazy_tls.Pointer()->Get() == this);
 
   // Signal this event before destroying the child process.  That way all
   // background threads can cleanup.
   // For example, in the renderer the RenderThread instances will be able to
   // notice shutdown before the render process begins waiting for them to exit.
@@ skipping 77 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