base: Support setting thread priorities generically.

base/threading/thread_restrictions.h

 // 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.
 
 #ifndef BASE_THREADING_THREAD_RESTRICTIONS_H_
 #define BASE_THREADING_THREAD_RESTRICTIONS_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 
@@ skipping 164 matching lines @@
   friend class ::HistogramSynchronizer;
   friend class ::ScopedAllowWaitForLegacyWebViewApi;
   friend class ::TestingAutomationProvider;
   friend class cc::CompletionEvent;
   friend class remoting::AutoThread;
   friend class MessagePumpDefault;
   friend class SequencedWorkerPool;
   friend class SimpleThread;
   friend class Thread;
   friend class ThreadTestHelper;
+  friend class PlatformThread;
 
   // END ALLOWED USAGE.
   // BEGIN USAGE THAT NEEDS TO BE FIXED.
   friend class ::chromeos::AudioMixerAlsa;        // http://crbug.com/125206
   friend class ::chromeos::BlockingMethodCaller;  // http://crbug.com/125360
   friend class ::chromeos::system::StatisticsProviderImpl;  // http://crbug.com/125385
   friend class browser_sync::NonFrontendDataTypeController;  // http://crbug.com/19757
   friend class browser_sync::UIModelWorker;       // http://crbug.com/19757
   friend class chrome_browser_net::Predictor;     // http://crbug.com/78451
   friend class
@@ skipping 35 matching lines @@
 
     DISALLOW_COPY_AND_ASSIGN(ScopedAllowWait);
   };
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ThreadRestrictions);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_THREAD_RESTRICTIONS_H_