Increase priority of raster threads on Android.

base/threading/platform_thread_linux.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 "base/threading/platform_thread.h"
 
 #include <errno.h>
 #include <sched.h>
 
 #include "base/lazy_instance.h"
@@ skipping 12 matching lines @@
 namespace base {
 
 namespace internal {
 
 namespace {
 #if !defined(OS_NACL)
 const struct sched_param kRealTimePrio = {8};
 #endif
 }  // namespace
 
-const ThreadPriorityToNiceValuePair kThreadPriorityToNiceValueMap[4] = {
+const ThreadPriorityToNiceValuePair kThreadPriorityToNiceValueMap[5] = {
     {ThreadPriority::BACKGROUND, 10},
+    {ThreadPriority::UI_BACKGROUND, 9},
     {ThreadPriority::NORMAL, 0},
     {ThreadPriority::DISPLAY, -6},
     {ThreadPriority::REALTIME_AUDIO, -10},
 };
 
 bool SetThreadPriorityForPlatform(PlatformThreadHandle handle,
                                   ThreadPriority priority) {
 #if !defined(OS_NACL)
   // TODO(gab): Assess the correctness of using |pthread_self()| below instead
   // of |handle|. http://crbug.com/468793.
@@ skipping 59 matching lines @@
 #if !defined(THREAD_SANITIZER)
   return 0;
 #else
   // ThreadSanitizer bloats the stack heavily. Evidence has been that the
   // default stack size isn't enough for some browser tests.
   return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).
 #endif
 }
 
 }  // namespace base