Added automatic mode to FakeInputAudioStream to generate automatic beeps

content/browser/renderer_host/media/audio_input_device_manager.cc

Index: content/browser/renderer_host/media/audio_input_device_manager.cc
diff --git a/content/browser/renderer_host/media/audio_input_device_manager.cc b/content/browser/renderer_host/media/audio_input_device_manager.cc
index 8d0377d859d63edd85d6da7fb5eae98370c143be..112d796e3ac80759a3179b2666d6fbfa13669214 100644
--- a/content/browser/renderer_host/media/audio_input_device_manager.cc
+++ b/content/browser/renderer_host/media/audio_input_device_manager.cc
@@ -19,6 +19,9 @@ namespace content {
 
 const int AudioInputDeviceManager::kFakeOpenSessionId = 1;
 
+const char kFakeDeviceName[] = "Fake Audio";
+const char kFakeDeviceId[] = "fake_audio";
+
 namespace {
 // Starting id for the first capture session.
 const int kFirstSessionId = AudioInputDeviceManager::kFakeOpenSessionId + 1;
@@ -32,8 +35,8 @@ AudioInputDeviceManager::AudioInputDeviceManager(
       audio_manager_(audio_manager) {
   // TODO(xians): Remove this fake_device after the unittests do not need it.
   StreamDeviceInfo fake_device(MEDIA_DEVICE_AUDIO_CAPTURE,
-                               media::AudioManagerBase::kDefaultDeviceName,
-                               media::AudioManagerBase::kDefaultDeviceId,
+                               kFakeDeviceName,
+                               kFakeDeviceName,

[DaleCurtis, 2014/04/29 17:33:31]

FakeDeviceId?

[no longer working on chromium, 2014/05/02 14:30:47]

Done.

                                44100, media::CHANNEL_LAYOUT_STEREO,
                                0);
   fake_device.session_id = kFakeOpenSessionId;
@@ -139,19 +142,18 @@ void AudioInputDeviceManager::EnumerateOnDeviceThread(
   }
 
   scoped_ptr<StreamDeviceInfoArray> devices(new StreamDeviceInfoArray());
-  for (media::AudioDeviceNames::iterator it = device_names.begin();
-       it != device_names.end(); ++it) {
-    // Add device information to device vector.
-    devices->push_back(StreamDeviceInfo(
-        stream_type, it->device_name, it->unique_id));
-  }
-
-  // If the |use_fake_device_| flag is on, inject the fake device if there is
-  // no available device on the OS.
-  if (use_fake_device_ && devices->empty()) {
-    devices->push_back(StreamDeviceInfo(
-        stream_type, media::AudioManagerBase::kDefaultDeviceName,
-        media::AudioManagerBase::kDefaultDeviceId));
+  // If the |use_fake_device_| flag is on or there is no available device on
+  // the OS, inject the fake device.
+  if (use_fake_device_ || devices->empty()) {

[DaleCurtis, 2014/04/29 17:33:31]

Won't devices() always be empty()? You're constructing it right here.

[phoglund_chromium, 2014/04/30 08:03:49]

Yeah, looks like the else branch will never be taken. You probably want to check
if device_names is empty.

[no longer working on chromium, 2014/05/02 14:30:47]

Ah, right, I just missed that devices were different from device_names. That
might be why lots of unittests failed, I looked deeper at those tests, it seems
that they mocked out the AudioManager and injected fake devices in the
enumeration APIs.
So I just fall back to the previous behavior and only inject the fake device if
the use_fake_device is true and there is no enumerated device.

[no longer working on chromium, 2014/05/02 14:30:47]

That was what I was thinking but realized that it would inject a fake device in
production when the list is empty, which is un-wanted change. Also some
unittests mocked out the AudioManager and injected fake devices in the
enumeration APIs. There is no easy way to change them to use
AudioInputDeviceManager().
So I just fall back to the previous behavior and only inject the fake device if
the use_fake_device is true and there is no enumerated device.

+    devices->push_back(StreamDeviceInfo(stream_type, kFakeDeviceName,
+                                        kFakeDeviceId));
+  } else {
+    for (media::AudioDeviceNames::iterator it = device_names.begin();
+         it != device_names.end(); ++it) {
+      // Add device information to device vector.
+      devices->push_back(StreamDeviceInfo(
+          stream_type, it->device_name, it->unique_id));
+    }

[DaleCurtis, 2014/04/29 17:33:31]

You're no longer injecting a fake device if no device is present.  Is this
intended?

[no longer working on chromium, 2014/05/02 14:30:47]

We don't inject the fake device in production. The previous code only inject the
fake device when use_fake_device_ is true (which is always false in production)
and devices->empty().

   }
 
   // Return the device list through the listener by posting a task on