Plumb audio focus support for spitzer clients.

media/blink/webaudiosourceprovider_impl.h

 // Copyright 2013 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_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_
 #define MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 22 matching lines @@
 // sample-frames using the sink's RenderCallback to get the data.
 //
 // All calls are protected by a lock.
 class MEDIA_BLINK_EXPORT WebAudioSourceProviderImpl
     : NON_EXPORTED_BASE(public blink::WebAudioSourceProvider),
       NON_EXPORTED_BASE(public RestartableAudioRendererSink) {
  public:
   explicit WebAudioSourceProviderImpl(
       const scoped_refptr<RestartableAudioRendererSink>& sink);
 
+  void enable_audio_focus() { enable_audio_focus_ = true; }

[mlamouri (slow - plz ping), 2016/01/19 17:18:17]

style: set_enable_audio_focus(bool), otherwise it looks like a getter.

[DaleCurtis, 2016/02/03 02:15:31]

There's no real preference over all of chrome (20 vs 21 hits), but favors
"enable_xxx()" in media/ (2 vs 0 :)
https://code.google.com/p/chromium/codesearch#search/&q=%22void%20enable_%22&...
https://code.google.com/p/chromium/codesearch#search/&q=%22void%20set_enable_...

I think enable_xxx() works better since a getter for such a variable would be
something like is_audio_focus_enabled().

+
   // blink::WebAudioSourceProvider implementation.
   void setClient(blink::WebAudioSourceProviderClient* client) override;
   void provideInput(const blink::WebVector<float*>& audio_data,
                     size_t number_of_frames) override;
 
   // RestartableAudioRendererSink implementation.
   void Start() override;
   void Stop() override;
   void Play() override;
   void Pause() override;
@@ skipping 25 matching lines @@
   AudioRendererSink::RenderCallback* renderer_;
 
   // When set via setClient() it overrides |sink_| for consuming audio.
   blink::WebAudioSourceProviderClient* client_;
 
   // Where audio ends up unless overridden by |client_|.
   base::Lock sink_lock_;
   scoped_refptr<RestartableAudioRendererSink> sink_;
   scoped_ptr<AudioBus> bus_wrapper_;
 
+  // If true, Initialize() will set AudioParamaters::FOCUSABLE.
+  bool enable_audio_focus_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<WebAudioSourceProviderImpl> weak_factory_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebAudioSourceProviderImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_WEBAUDIOSOURCEPROVIDER_IMPL_H_