Remove volume level DCHECK in WebRtcAudioCapturer on CrOS

As per discussion in the associated bug, this DCHECK may not make sense
on CrOS.

BUG=chrome-os-partner:29388
TEST=Run Debug Chrome, DCHECK not hit

Review URL: https://codereview.chromium.org/315073004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275392 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/media/webrtc_audio_capturer.cc

@@ -457,7 +457,7 @@ void WebRtcAudioCapturer::Capture(media::AudioBus* audio_source,
 // CaptureCallback.
 #if defined(OS_WIN) || defined(OS_MACOSX)
   DCHECK_LE(volume, 1.0);
-#elif defined(OS_LINUX) || defined(OS_OPENBSD)
+#elif (defined(OS_LINUX) && !defined(OS_CHROMEOS)) || defined(OS_OPENBSD)
   // We have a special situation on Linux where the microphone volume can be
   // "higher than maximum". The input volume slider in the sound preference
   // allows the user to set a scaling that is higher than 100%. It means that