Refactor: Make MediaCaptureDevicesDispatcher have pluggable handlers.

chrome/browser/media/permission_bubble_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_PERMISSION_BUBBLE_MEDIA_ACCESS_HANDLER_H_
+#define CHROME_BROWSER_MEDIA_PERMISSION_BUBBLE_MEDIA_ACCESS_HANDLER_H_
+
+#include <deque>
+#include <map>
+
+#include "chrome/browser/media/media_access_handler.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+struct PendingAccessRequest {

[Sergey Ulanov, 2015/06/01 23:39:18]

this can be nested in PermissionBubbleMediaAccessHandler. Also you don't need to
define the class in the header. Just declare it and move definition to the .cc
file.

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

Done.

+  PendingAccessRequest(const content::MediaStreamRequest& request,
+                       const content::MediaResponseCallback& callback);
+  ~PendingAccessRequest();
+
+  // TODO(gbillock): make the MediaStreamDevicesController owned by
+  // this object when we're using bubbles.
+  content::MediaStreamRequest request;
+  content::MediaResponseCallback callback;
+};
+
+class PermissionBubbleMediaAccessHandler
+    : public MediaAccessHandler,
+      public content::NotificationObserver {
+ public:
+  PermissionBubbleMediaAccessHandler();
+  ~PermissionBubbleMediaAccessHandler() override;
+
+  // MediaAccessHandler implementation.
+  bool SupportsStreamType(const content::MediaStreamType type,
+                          const extensions::Extension* extension) override;
+  bool CheckMediaAccessPermission(
+      content::WebContents* web_contents,
+      const GURL& security_origin,
+      content::MediaStreamType type,
+      const extensions::Extension* extension) override;
+  void HandleRequest(content::WebContents* web_contents,
+                     const content::MediaStreamRequest& request,
+                     const content::MediaResponseCallback& callback,
+                     const extensions::Extension* extension) override;
+  void UpdateMediaRequest(int render_process_id,
+                          int render_frame_id,
+                          int page_request_id,
+                          content::MediaStreamType stream_type,
+                          content::MediaRequestState state) override;
+
+ private:
+  void ProcessQueuedAccessRequest(content::WebContents* web_contents);
+  void OnAccessRequestResponse(content::WebContents* web_contents,
+                               const content::MediaStreamDevices& devices,
+                               content::MediaStreamRequestResult result,
+                               scoped_ptr<content::MediaStreamUI> ui);
+
+  // content::NotificationObserver implementation.
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
+  typedef std::deque<PendingAccessRequest> RequestsQueue;

[Sergey Ulanov, 2015/06/01 23:39:18]

please move before other private methods:
https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Declaration_...

+  typedef std::map<content::WebContents*, RequestsQueue> RequestsQueues;
+  RequestsQueues pending_requests_;
+  content::NotificationRegistrar notifications_registrar_;
+};
+#endif  // CHROME_BROWSER_MEDIA_PERMISSION_BUBBLE_MEDIA_ACCESS_HANDLER_H_