Limit the max volume to 255 before pass it to APM.

content/renderer/media/webrtc_audio_capturer.cc

Index: content/renderer/media/webrtc_audio_capturer.cc
diff --git a/content/renderer/media/webrtc_audio_capturer.cc b/content/renderer/media/webrtc_audio_capturer.cc
index 482d25f1114b2479baabcda0d4fb930c4e5ba944..b1bb2741aa8616609a71d6cb573c7e56e3320a58 100644
--- a/content/renderer/media/webrtc_audio_capturer.cc
+++ b/content/renderer/media/webrtc_audio_capturer.cc
@@ -464,7 +464,7 @@ void WebRtcAudioCapturer::Capture(media::AudioBus* audio_source,
     // webrtc::VoiceEngine. webrtc::VoiceEngine will handle the case when the
     // volume is higher than 255.

[ajm, 2014/04/12 01:53:34]

Update this comment, since VoiceEngine isn't handling this any more, and mention
why we need to clamp it.

[no longer working on chromium, 2014/04/14 10:06:33]

Done.

     volume_ = static_cast<int>((volume * MaxVolume()) + 0.5);
-    current_volume = volume_;
+    current_volume = volume_ > MaxVolume() ? MaxVolume() : volume_;
     audio_delay = base::TimeDelta::FromMilliseconds(audio_delay_milliseconds);
     audio_delay_ = audio_delay;
     key_pressed_ = key_pressed;