Small refactor to media architecture in order to allow end-to-end tests.

media/audio/audio_manager.cc

Index: media/audio/audio_manager.cc
diff --git a/media/audio/audio_manager.cc b/media/audio/audio_manager.cc
index 028b409149187c78bf9536df07cf16570b59106a..495673bb352cc8d3e340f9733b44b76a5c0cb7ea 100644
--- a/media/audio/audio_manager.cc
+++ b/media/audio/audio_manager.cc
@@ -10,6 +10,8 @@
 
 namespace media {
 
+AudioManager* AudioManager::audio_manager_for_tests_ = NULL;
+
 // Forward declaration of the platform specific AudioManager factory function.
 AudioManager* CreateAudioManager();
 
@@ -21,9 +23,16 @@ AudioManager::~AudioManager() {
 
 // static
 AudioManager* AudioManager::Create() {
+  if (audio_manager_for_tests_)
+    return audio_manager_for_tests_;
   AudioManager* ret = CreateAudioManager();
   ret->Init();
   return ret;
 }
 
+// static
+void AudioManager::set_audio_manager_for_tests(AudioManager* audio_manager) {
+  audio_manager_for_tests_ = audio_manager;
+}
+
 }  // namespace media