cros: Enable new cras audio handler by default

chromeos/audio/cras_audio_handler.cc

Index: chromeos/audio/cras_audio_handler.cc
diff --git a/chromeos/audio/cras_audio_handler.cc b/chromeos/audio/cras_audio_handler.cc
index b374402baa7acb3383e7b7ce26a0aa41756fd103..a0980a69c195a29688f2a8c801ee0ad5a6e44bc0 100644
--- a/chromeos/audio/cras_audio_handler.cc
+++ b/chromeos/audio/cras_audio_handler.cc
@@ -11,6 +11,7 @@
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "chromeos/audio/audio_pref_handler.h"
+#include "chromeos/audio/mock_cras_audio_handler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 
 using std::max;
@@ -63,6 +64,12 @@ void CrasAudioHandler::Initialize(
 }
 
 // static
+void CrasAudioHandler::InitializeForTesting() {
+  CHECK(!g_cras_audio_handler);
+  g_cras_audio_handler = new MockCrasAudioHandler();
+}
+
+// static
 void CrasAudioHandler::Shutdown() {
   CHECK(g_cras_audio_handler);
   delete g_cras_audio_handler;
@@ -191,13 +198,24 @@ CrasAudioHandler::CrasAudioHandler(
       has_alternative_output_(false),
       output_mute_locked_(false),
       input_mute_locked_(false) {
+  if (!audio_pref_handler)
+    return;
+  // If the DBusThreadManager or the CrasAudioClient aren't available, there
+  // isn't much we can do. This should only happen when running tests.
+  if (!chromeos::DBusThreadManager::IsInitialized() ||
+      !chromeos::DBusThreadManager::Get() ||
+      !chromeos::DBusThreadManager::Get()->GetCrasAudioClient())
+    return;
   chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->AddObserver(this);
-  DCHECK(audio_pref_handler_.get());
   audio_pref_handler_->AddAudioPrefObserver(this);
   SetupInitialAudioState();
 }
 
 CrasAudioHandler::~CrasAudioHandler() {
+  if (!chromeos::DBusThreadManager::IsInitialized() ||

[James Cook, 2013/04/30 23:31:21]

Do you need to check audio_pref_handler_ here?

[rkc, 2013/04/30 23:36:37]

Yeah; in case we're running in a test, we also need to make sure we don't try to
"remove" an observer either - with the MockDBusThreadManager, GetCrasAudioClient
is NULL and at certain tests the DBusThreadManager can be NULL too.

+      !chromeos::DBusThreadManager::Get() ||
+      !chromeos::DBusThreadManager::Get()->GetCrasAudioClient())
+    return;
   chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
       RemoveObserver(this);
   audio_pref_handler_->RemoveAudioPrefObserver(this);