Avoid reporting 0 as input level when AudioProcessing zero out the audio data

content/renderer/media/media_stream_audio_level_calculator.h

Index: content/renderer/media/media_stream_audio_level_calculator.h
diff --git a/content/renderer/media/media_stream_audio_level_calculator.h b/content/renderer/media/media_stream_audio_level_calculator.h
index 41c9c34f7be1b2f803941ca2429417ddc8eb4fdc..970c08d72fd979de52ec25114034589fcb1c2256 100644
--- a/content/renderer/media/media_stream_audio_level_calculator.h
+++ b/content/renderer/media/media_stream_audio_level_calculator.h
@@ -22,7 +22,7 @@ class MediaStreamAudioLevelCalculator {
   // Calculates the signal level of the audio data.
   // Returns the absolute value of the amplitude of the signal.
   int Calculate(const int16* audio_data, int number_of_channels,
-                int number_of_frames);
+                int number_of_frames, bool has_energy);

[tommi (sloooow) - chröme, 2014/10/17 11:59:08]

can you add documentation for the new parameter?  It's got a very special
purpose so I think it's important to make it clear.

I also think that the name of the parameter is misleading.  In most call sites,
you're passing false now, which will be interpreted as "the input audio data has
no energy" and that's not correct.  I think we should go with something like
force_nonzero_energy or perhaps always_assume_energy.

Btw, just looking at the prototype for this function now, I would wonder why
this flag isn't simply calculated inside the implementation of Calculate since
the audio_data is being passed to the function.  So why the parameter is needed
separate of the data, also needs to be documented.

[no longer working on chromium, 2014/10/20 08:08:42]

All done, please take a look.
Thanks.

 
  private:
   // Used to DCHECK that the constructor and Calculate() are always called on