content: Implement dynamic priorities for raster threads.

base/threading/platform_thread_mac.mm

 // 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"
 
 #import <Foundation/Foundation.h>
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 #include <mach/thread_policy.h>
@@ skipping 163 matching lines @@
       break;
   }
 }
 
 // static
 ThreadPriority PlatformThread::GetCurrentThreadPriority() {
   NOTIMPLEMENTED();
   return ThreadPriority::NORMAL;
 }
 
+// static
+bool PlatformThread::SetChildThreadPriorityInCurrentProcess(
+    PlatformThreadHandle thread_handle,
+    PlatformThreadId tid,
+    ThreadPriority priority) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
 #if defined(OS_IOS)
   return 0;
 #else
   // The Mac OS X default for a pthread stack size is 512kB.
   // Libc-594.1.4/pthreads/pthread.c's pthread_attr_init uses
   // DEFAULT_STACK_SIZE for this purpose.
   //
   // 512kB isn't quite generous enough for some deeply recursive threads that
   // otherwise request the default stack size by specifying 0. Here, adopt
@@ skipping 19 matching lines @@
                  static_cast<size_t>(stack_rlimit.rlim_cur));
   }
   return default_stack_size;
 #endif
 }
 
 void TerminateOnThread() {
 }
 
 }  // namespace base