Reduce power logging and UMA stats when AGC is disabled

content/browser/renderer_host/media/audio_input_renderer_host.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 "content/browser/renderer_host/media/audio_input_renderer_host.h"
 
 #include "base/bind.h"
 #include "base/memory/shared_memory.h"
 #include "base/metrics/histogram.h"
 #include "base/numerics/safe_math.h"
@@ skipping 371 matching lines @@
         audio_manager_->GetTaskRunner(),
         this,
         WebContentsAudioInputStream::Create(
             device_id,
             audio_params,
             audio_manager_->GetWorkerTaskRunner(),
             audio_mirroring_manager_),
         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()) {
     SendErrorMessage(stream_id, STREAM_CREATE_ERROR);
     MaybeUnregisterKeyboardMicStream(config);
     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) {
     entry->has_keyboard_mic_ = true;
   }
 #endif
 
   MediaStreamManager::SendMessageToNativeLog(oss.str());
   DVLOG(1) << oss.str();
 
@@ skipping 129 matching lines @@
 #if defined(OS_CHROMEOS)
   if (config.params.channel_layout() ==
       media::CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC) {
     media_stream_manager_->audio_input_device_manager()
         ->UnregisterKeyboardMicStream();
   }
 #endif
 }
 
 }  // namespace content