Yeah, I noticed that a couple of days ago, but failed to file an issue on it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7b308a54ce405471a43e12ea7a65952439127d17

commit 7b308a54ce405471a43e12ea7a65952439127d17
Author: rtoy <rtoy@chromium.org>
Date: Tue Dec 20 17:23:47 2016

Add constructor for MediaStreamAudioDestinationNode

MediaStreamAudioDestinationNode needs a constructor.  This was
inadvertently missed in  issue 626449 .

Also, modified the exception type when an invalid channel count is
specified.  All other AudioNodes throw NotSupportedError instead of
IndexSizeError.  This requires updating one test.

BUG= 674508 ,  626449 
TEST=constructor/mediastreamaudiodestination.html,
mediastreamaudiodestinationnode.html

Review-Url: https://codereview.chromium.org/2578243002
Cr-Commit-Position: refs/heads/master@{#439833}

[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/LayoutTests/webaudio/MediaStreamAudioDestination/mediastreamaudiodestinationnode-expected.txt
[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/LayoutTests/webaudio/MediaStreamAudioDestination/mediastreamaudiodestinationnode.html
[add] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/LayoutTests/webaudio/constructor/mediastreamaudiodestination.html
[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/Source/core/frame/UseCounter.h
[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.cpp
[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h
[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.idl
[modify] https://crrev.com/7b308a54ce405471a43e12ea7a65952439127d17/tools/metrics/histograms/histograms.xml