Fix hotword module constantly restarting on Pixel 2.

content/renderer/media/user_media_client_impl.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/renderer/media/user_media_client_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 51 matching lines @@
   if (!request.audioConstraints().isNull()) {
     const blink::WebMediaTrackConstraintSet& audio_basic =
         request.audioConstraints().basic();
     CopyFirstString(audio_basic.mediaStreamSource.exact(),
                     &(controls->audio.stream_source));
     CopyVector(audio_basic.deviceId.exact(), &(controls->audio.device_ids));
     // Optionals. They may be either in ideal or in advanced.exact.
     // TODO(hta): Get alternatives only mentioned in advanced array.
     CopyVector(audio_basic.deviceId.ideal(),
                &controls->audio.alternate_device_ids);
-    if (!audio_basic.hotwordEnabled.matches(false))
-      controls->hotword_enabled = true;
+
+    for (const auto& audio_advanced : request.audioConstraints().advanced()) {
+      if (!audio_advanced.hotwordEnabled.matches(false))
+        controls->hotword_enabled = true;

[hta - Chromium, 2016/02/26 11:35:44]

1) put a break in this loop.

2) instead use
  if (audio_basic.hasExact()) {
     controls->hotword_enabled =    
        audio_advanced.hotwordEnabled.exact();
  } else {
    if(audio_advanced.hotwordEnabled.hasExact()) {
     controls->hotword_enabled =      
         audio_advanced.hotwordEnabled.exact();
     break;
  }

Yes, there's an utility function to do this, but it's in a CL that hasn't been
submitted yet :-(

3) write an unit test!

[Anand Mistry (off Chromium), 2016/02/29 02:10:07]

Done.
Done.
And there's the problem. It looks like this code doesn't have any unit tests. In
fact, I'm not sure I can write any unit tests given this nugget of comment in
UserMediaClientImpl::requestUserMedia():
// |user_media_request| can't be mocked. So in order to test at all we check
// if it isNull.

+    }
   }
   if (!request.videoConstraints().isNull()) {
     const blink::WebMediaTrackConstraintSet& video_basic =
         request.videoConstraints().basic();
     CopyFirstString(video_basic.mediaStreamSource.exact(),
                     &(controls->video.stream_source));
     CopyVector(video_basic.deviceId.exact(), &(controls->video.device_ids));
     CopyVector(video_basic.deviceId.ideal(),
                &(controls->video.alternate_device_ids));
   }
@@ skipping 1049 matching lines @@
       return;
     }
   }
 }
 
 bool UserMediaClientImpl::UserMediaRequestInfo::HasPendingSources() const {
   return !sources_waiting_for_callback_.empty();
 }
 
 }  // namespace content