Reland: MediaCaptureFromElement: add support for audio captureStream().

third_party/WebKit/Source/modules/mediacapturefromelement/HTMLMediaElementCapture.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/mediacapturefromelement/HTMLMediaElementCapture.h"
 
 #include "core/dom/ExceptionCode.h"
 #include "core/html/HTMLMediaElement.h"
+#include "core/html/track/AudioTrackList.h"
+#include "core/html/track/VideoTrackList.h"
 #include "modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h"
 #include "modules/encryptedmedia/MediaKeys.h"
 #include "modules/mediastream/MediaStream.h"
 #include "modules/mediastream/MediaStreamRegistry.h"
 #include "platform/mediastream/MediaStreamCenter.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebMediaStream.h"
 #include "public/platform/WebMediaStreamTrack.h"
 
 namespace blink {
@@ skipping 11 matching lines @@
         // This exception is not defined in the spec, see https://github.com/w3c/mediacapture-fromelement/issues/20.
         exceptionState.throwDOMException(NotSupportedError, "Stream capture not supported with EME");
         return nullptr;
     }
 
     // If |element| is actually playing a MediaStream, just clone it.
     if (HTMLMediaElement::isMediaStreamURL(element.currentSrc().getString())) {
         return MediaStream::create(element.getExecutionContext(), MediaStreamRegistry::registry().lookupMediaStreamDescriptor(element.currentSrc().getString()));
     }
 
-    // TODO(mcasas): Only <video> tags are supported at the moment.
-    if (element.isHTMLAudioElement()) {
-        NOTIMPLEMENTED();
-        return nullptr;
-    }
-
     WebMediaStream webStream;
     webStream.initialize(WebVector<WebMediaStreamTrack>(), WebVector<WebMediaStreamTrack>());
     MediaStreamCenter::instance().didCreateMediaStream(webStream);
 
-    Platform::current()->createHTMLVideoElementCapturer(&webStream, element.webMediaPlayer());
+    if (element.hasVideo())
+        Platform::current()->createHTMLVideoElementCapturer(&webStream, element.webMediaPlayer());
+    if (element.hasAudio())
+        Platform::current()->createHTMLAudioElementCapturer(&webStream, element.webMediaPlayer());
     return MediaStream::create(element.getExecutionContext(), webStream);
 }
 
 } // namespace blink