Reduce power logging and UMA stats when AGC is disabled

content/browser/renderer_host/media/audio_input_renderer_host.cc

Index: content/browser/renderer_host/media/audio_input_renderer_host.cc
diff --git a/content/browser/renderer_host/media/audio_input_renderer_host.cc b/content/browser/renderer_host/media/audio_input_renderer_host.cc
index 83aa43cf4ba9322da6a754578030631b177f0d03..62c1e4268b460f52e8a10975180df69520166c95 100644
--- a/content/browser/renderer_host/media/audio_input_renderer_host.cc
+++ b/content/browser/renderer_host/media/audio_input_renderer_host.cc
@@ -389,16 +389,21 @@ void AudioInputRendererHost::DoCreateStream(
         entry->writer.get(),
         user_input_monitor_);
   } else {
-    // TODO(henrika): replace CreateLowLatency() with Create() as soon
-    // as satish has ensured that Speech Input also uses the default low-
-    // latency path. See crbug.com/112472 for details.
+    // Set the initial AGC state for the audio input stream. Note that, the AGC
+    // is only supported in AUDIO_PCM_LOW_LATENCY mode.
+    const bool agc_is_enabled =
+        config.params.format() ==
+            media::AudioParameters::AUDIO_PCM_LOW_LATENCY &&

[tommi (sloooow) - chröme, 2014/10/20 16:03:28]

if format() is not 'low latency' bug we call CreateLowLatency here regardless,
is that a bug?

I'm wondering if we should just pass config.automatic_gain_control and skip the
temporary variable.
(and possibly DCHECK on AUDIO_PCM_LOW_LATENCY)

[henrika (OOO until Aug 14), 2014/10/21 08:00:28]

Good point. I had the same idea but did not want to change too much. But you are
correct. We might as well make the change now.

+        config.automatic_gain_control;
+    oss << ", AGC=" << agc_is_enabled;
     entry->controller =
         media::AudioInputController::CreateLowLatency(audio_manager_,
                                                       this,
                                                       audio_params,
                                                       device_id,
                                                       entry->writer.get(),
-                                                      user_input_monitor_);
+                                                      user_input_monitor_,
+                                                      agc_is_enabled);
   }
 
   if (!entry->controller.get()) {
@@ -407,13 +412,6 @@ void AudioInputRendererHost::DoCreateStream(
     return;
   }
 
-  // Set the initial AGC state for the audio input stream. Note that, the AGC
-  // is only supported in AUDIO_PCM_LOW_LATENCY mode.
-  if (config.params.format() == media::AudioParameters::AUDIO_PCM_LOW_LATENCY) {
-    entry->controller->SetAutomaticGainControl(config.automatic_gain_control);
-    oss << ", AGC=" << config.automatic_gain_control;
-  }
-
 #if defined(OS_CHROMEOS)
   if (config.params.channel_layout() ==
           media::CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC) {