Add sample rates checking in MediaStreamAudioProcessor

content/renderer/media/media_stream_audio_processor.cc

Index: content/renderer/media/media_stream_audio_processor.cc
diff --git a/content/renderer/media/media_stream_audio_processor.cc b/content/renderer/media/media_stream_audio_processor.cc
index 23547d1b2b6490331f28d0110284f523044e1d57..b2a6215dc562f62cc78c8249cf531decc8c479fa 100644
--- a/content/renderer/media/media_stream_audio_processor.cc
+++ b/content/renderer/media/media_stream_audio_processor.cc
@@ -16,6 +16,7 @@
 #include "media/base/audio_converter.h"
 #include "media/base/audio_fifo.h"
 #include "media/base/channel_layout.h"
+#include "media/base/limits.h"
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
 #include "third_party/libjingle/source/talk/app/webrtc/mediaconstraintsinterface.h"
 #include "third_party/webrtc/modules/audio_processing/typing_detection.h"
@@ -137,7 +138,8 @@ class MediaStreamAudioFifo {
            new MediaStreamAudioBus(destination_channels, destination_frames)),
        data_available_(false) {
     DCHECK_GE(source_channels, destination_channels);
-    DCHECK_GT(sample_rate_, 0);
+    DCHECK_GE(sample_rate_, media::limits::kMinSampleRate);

[Henrik Grunell, 2015/09/30 08:19:25]

I was thinking to test the set of explicit samples rates that we support, e.g.
8000, 16000, and so on. However I don't know exactly what we support and if
that's defined somewhere. Deferring to Henrik A to answer that.

[henrika (OOO until Aug 14), 2015/09/30 08:49:18]

Have not done the latest changes in this area and can't say for sure but it
seems like we support "all rates". See
https://code.google.com/p/chromium/codesearch#chromium/src/content/renderer/m...
and\
https://code.google.com/p/chromium/codesearch#chromium/src/media/audio/sample...

+    DCHECK_LE(sample_rate_, media::limits::kMaxSampleRate);
 
     if (source_channels > destination_channels) {
       audio_source_intermediate_ =