Refactor: Make MediaCaptureDevicesDispatcher have pluggable handlers.

chrome/browser/media/media_access_handler.h

+// 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.
+
+#ifndef CHROME_BROWSER_MEDIA_MEDIA_ACCESS_HANDLER_H_
+#define CHROME_BROWSER_MEDIA_MEDIA_ACCESS_HANDLER_H_
+
+#include "base/callback.h"
+#include "content/public/browser/media_request_state.h"
+#include "content/public/common/media_stream_request.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace extensions {
+class Extension;
+}
+
+// Interface for handling media access requests that are propagated from
+// MediaCaptureDevicesDispatcher.
+class MediaAccessHandler {
+ public:
+  MediaAccessHandler() {}
+  virtual ~MediaAccessHandler() {}
+
+  virtual bool SupportsStreamType(const content::MediaStreamType type,

[Sergey Ulanov, 2015/06/01 23:39:17]

add a short comment for each method to describe its purpose.

[changbin, 2015/06/02 14:20:09]

Done.

+                                  const extensions::Extension* extension) = 0;
+  virtual bool CheckMediaAccessPermission(
+      content::WebContents* web_contents,
+      const GURL& security_origin,
+      content::MediaStreamType type,
+      const extensions::Extension* extension) = 0;
+  virtual void HandleRequest(content::WebContents* web_contents,
+                             const content::MediaStreamRequest& request,
+                             const content::MediaResponseCallback& callback,
+                             const extensions::Extension* extension) = 0;
+  virtual void UpdateMediaRequest(int render_process_id,

[Sergey Ulanov, 2015/06/01 23:39:17]

call it UpdateMediaRequestState()?

+                                  int render_frame_id,
+                                  int page_request_id,
+                                  content::MediaStreamType stream_type,
+                                  content::MediaRequestState state) {}
+};
+
+#endif  // CHROME_BROWSER_MEDIA_MEDIA_ACCESS_HANDLER_H_