MediaRecorder: add and wire read {video,audio}BitsPerSecond props

third_party/WebKit/LayoutTests/fast/mediarecorder/MediaRecorder-creation.html

Index: third_party/WebKit/LayoutTests/fast/mediarecorder/MediaRecorder-creation.html
diff --git a/third_party/WebKit/LayoutTests/fast/mediarecorder/MediaRecorder-creation.html b/third_party/WebKit/LayoutTests/fast/mediarecorder/MediaRecorder-creation.html
index f6e32d45869b669d624276c5f57bb03cf8cded81..bb1d03e4feba194bd1d1452137e934e4472a6f6d 100644
--- a/third_party/WebKit/LayoutTests/fast/mediarecorder/MediaRecorder-creation.html
+++ b/third_party/WebKit/LayoutTests/fast/mediarecorder/MediaRecorder-creation.html
@@ -19,6 +19,8 @@ function makeAsyncTest(constraints, verifyStream, message) {
                 assert_unreached('Exception while creating MediaRecorder: ' + e);
             }
             assert_equals(recorder.state, "inactive");
+            assert_equals(recorder.videoBitsPerSecond, 0);

[philipj_slow, 2016/02/03 03:31:05]

That seems weird, why shouldn't this return the default bitrate being targeted,
just like mimeType should return the default MIME type chosen?

[mcasas, 2016/02/03 23:50:27]

Because the bitrate, when left by JS as undefined,
means is left to the encoder. In this case, it basically
means 0 to signify that the encoders were left to 
decide it (and update it as they see fit). Sense?

[philipj_slow, 2016/02/04 03:03:10]

Well, the encoder isn't really targeting a zero bitrate, why not set it to the
actually targeted bitrate? The reasoning being that creating a new
MediaRecorder({ audioBitsPerSecond: other.audioBitsPerSecond,
videoBitsPerSecond: other.videoBitsPerSecond }) should result exactly the same
bitrate config as other, and it's reasonable to leave zero to mean "minimum
bitrate possible."

+            assert_equals(recorder.audioBitsPerSecond, 0);
             test.done();
         });