Adds method to provide custom AudioManager at runtime.

media/audio/audio_manager.cc

 // 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 "media/audio/audio_manager.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/debug/alias.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/power_monitor/power_monitor.h"
 #include "build/build_config.h"
+#include "media/audio/audio_manager_factory.h"
 #include "media/audio/fake_audio_log_factory.h"
 
 namespace media {
 namespace {
+
+// The singleton instance of AudioManager. This is set when Create() is called.
 AudioManager* g_last_created = NULL;
 
+// The singleton instance of AudioManagerFactory. This is only set if
+// SetFactory() is called. If it is set when Create() is called, its
+// CreateInstance() function is used to set |g_last_created|. Otherwise, the
+// linked implementation of media::CreateAudioManager is used to set
+// |g_last_created|.
+AudioManagerFactory* g_audio_manager_factory = NULL;
+
 // Maximum number of failed pings to the audio thread allowed. A crash will be
 // issued once this count is reached.  We require at least two pings before
 // crashing to ensure unobservable power events aren't mistakenly caught (e.g.,
 // the system suspends before a OnSuspend() event can be fired.).
 const int kMaxHangFailureCount = 2;
 
 // Helper class for managing global AudioManager data and hang timers. If the
 // audio thread is unresponsive for more than two minutes we want to crash the
 // process so we can catch offenders quickly in the field.
 class AudioManagerHelper : public base::PowerObserver {
@@ skipping 85 matching lines @@
   base::Lock hang_lock_;
   bool hang_detection_enabled_;
   base::TimeTicks last_audio_thread_timer_tick_;
   int hang_failures_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerHelper);
 };
 
 static base::LazyInstance<AudioManagerHelper>::Leaky g_helper =
     LAZY_INSTANCE_INITIALIZER;
-}
+}  // namespace
 
 // Forward declaration of the platform specific AudioManager factory function.
 AudioManager* CreateAudioManager(AudioLogFactory* audio_log_factory);
 
 AudioManager::AudioManager() {}
 
 AudioManager::~AudioManager() {
   CHECK(!g_last_created || g_last_created == this);
   g_last_created = NULL;
 }
 
 // static
+void AudioManager::SetFactory(AudioManagerFactory* factory) {
+  CHECK(factory);
+  CHECK(!g_last_created);
+  CHECK(!g_audio_manager_factory);
+  g_audio_manager_factory = factory;
+}
+
+// static
+void AudioManager::ResetFactoryForTesting() {
+  if (g_audio_manager_factory) {
+    delete g_audio_manager_factory;
+    g_audio_manager_factory = nullptr;
+  }
+}
+
+// static
 AudioManager* AudioManager::Create(AudioLogFactory* audio_log_factory) {
   CHECK(!g_last_created);
-  g_last_created = CreateAudioManager(audio_log_factory);
+  if (g_audio_manager_factory)
+    g_last_created = g_audio_manager_factory->CreateInstance(audio_log_factory);
+  else
+    g_last_created = CreateAudioManager(audio_log_factory);
+
   return g_last_created;
 }
 
 // static
 AudioManager* AudioManager::CreateWithHangTimer(
     AudioLogFactory* audio_log_factory,
     const scoped_refptr<base::SingleThreadTaskRunner>& monitor_task_runner) {
   AudioManager* manager = Create(audio_log_factory);
   // On OSX the audio thread is the UI thread, for which a hang monitor is not
   // necessary.
 #if !defined(OS_MACOSX)
   g_helper.Pointer()->StartHangTimer(monitor_task_runner);
 #endif
   return manager;
 }
 
 // static
 AudioManager* AudioManager::CreateForTesting() {
   return Create(g_helper.Pointer()->fake_log_factory());
 }
 
 // static
 AudioManager* AudioManager::Get() {
   return g_last_created;
 }
 
 }  // namespace media