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

content/renderer/media/media_stream_audio_level_calculator.cc

Index: content/renderer/media/media_stream_audio_level_calculator.cc
diff --git a/content/renderer/media/media_stream_audio_level_calculator.cc b/content/renderer/media/media_stream_audio_level_calculator.cc
index a136e32ae1009dbe87139f04a687a3a038d4ac69..33f3c5314b040fdf83e80b1801626fc3f94ae232 100644
--- a/content/renderer/media/media_stream_audio_level_calculator.cc
+++ b/content/renderer/media/media_stream_audio_level_calculator.cc
@@ -40,7 +40,8 @@ MediaStreamAudioLevelCalculator::~MediaStreamAudioLevelCalculator() {
 
 int MediaStreamAudioLevelCalculator::Calculate(const int16* audio_data,
                                                int number_of_channels,
-                                               int number_of_frames) {
+                                               int number_of_frames,
+                                               bool has_energy) {
   DCHECK(thread_checker_.CalledOnValidThread());
   // |level_| is updated every 10 callbacks. For the case where callback comes
   // every 10ms, |level_| will be updated approximately every 100ms.
@@ -50,7 +51,7 @@ int MediaStreamAudioLevelCalculator::Calculate(const int16* audio_data,
   max_amplitude_ = std::max(max_amplitude_, max);
 
   if (counter_++ == kUpdateFrequency) {
-    level_ = max_amplitude_;
+    level_ = (max_amplitude_ == 0 ? has_energy : max_amplitude_);
 
     // Decay the absolute maximum amplitude by 1/4.
     max_amplitude_ >>= 2;