Add srcObject attribute of type MediaStream to HTMLMediaElement.

content/renderer/media/web_media_element_source_utils.h

Index: content/renderer/media/web_media_element_source_utils.h
diff --git a/content/renderer/media/web_media_element_source_utils.h b/content/renderer/media/web_media_element_source_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..296399d522d754c44485207133aa78abc73dc51a
--- /dev/null
+++ b/content/renderer/media/web_media_element_source_utils.h
@@ -0,0 +1,23 @@
+// Copyright 2016 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.
+
+#ifndef CONTENT_RENDERER_MEDIA_WEB_MEDIA_ELEMENT_SOURCE_UTILS_H_
+#define CONTENT_RENDERER_MEDIA_WEB_MEDIA_ELEMENT_SOURCE_UTILS_H_
+
+namespace blink {
+class WebMediaElementSource;
+class WebMediaStream;
+}
+
+namespace content {
+
+// Obtains a WebMediaStream from a WebMediaElementSource. If the
+// WebMediaElementSource does not contain a WebMediaStream, a null
+// WebMediaStream is returned.
+blink::WebMediaStream GetWebMediaStreamFromWebMediaElementSource(
+    const blink::WebMediaElementSource& source);
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_WEB_MEDIA_ELEMENT_SOURCE_UTILS_H_