app_shell: Add audio and video capture support

extensions/shell/browser/media_capture_util.h

+// Copyright 2014 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 EXTENSIONS_SHELL_BROWSER_MEDIA_CAPTURE_UTIL_H_
+#define EXTENSIONS_SHELL_BROWSER_MEDIA_CAPTURE_UTIL_H_
+
+#include "base/macros.h"
+#include "content/public/common/media_stream_request.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace extensions {
+namespace media_capture_util {
+
+// Grants access to the first available audio capture device (if requested) and
+// the first available video capture device (if requested). Usually used as a
+// helper for media capture ProcessMediaAccessRequest().
+void GrantMediaStreamRequestWithFirstDevice(
+    content::WebContents* web_contents,
+    const content::MediaStreamRequest& request,
+    const content::MediaResponseCallback& callback);
+
+}  // namespace media_capture_util
+}  // namespace extensions
+
+#endif  // EXTENSIONS_SHELL_BROWSER_MEDIA_CAPTURE_UTIL_H_