Make OS audio buffer size limits visible.

media/audio/audio_manager.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 MEDIA_AUDIO_AUDIO_MANAGER_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 169 matching lines @@
 
   // Disable output debug recording.
   virtual void DisableOutputDebugRecording() = 0;
 
   // Gets the name of the audio manager (e.g., Windows, Mac, PulseAudio).
   virtual const char* GetName() = 0;
 
   // Limits the number of streams that can be created for testing purposes.
   virtual void SetMaxStreamCountForTesting(int max_input, int max_output);
 
+  // Get the minimum and maximum audio buffer sizes. The definitions exist in
+  // the specific AudioManager implementations.
+  static int GetMinimumAudioBufferSize(int sample_rate);
+  static int GetMaximumAudioBufferSize(int sample_rate);
+
  protected:
   FRIEND_TEST_ALL_PREFIXES(AudioManagerTest, AudioDebugRecording);
   friend class AudioDeviceInfoAccessorForTests;
 
   explicit AudioManager(std::unique_ptr<AudioThread> audio_thread);
 
   virtual void ShutdownOnAudioThread() = 0;
 
   // Initializes output debug recording. Can be called on any thread; will post
   // to the audio thread if not called on it.
@@ skipping 69 matching lines @@
   std::unique_ptr<AudioThread> audio_thread_;
   bool shutdown_ = false;  // True after |this| has been shutdown.
 
   THREAD_CHECKER(thread_checker_);
   DISALLOW_COPY_AND_ASSIGN(AudioManager);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_H_