Move ChromeOS login media access logic into a MediaAccessHandler

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() {}
 
   // Check if the media stream type is supported by MediaAccessHandler.
-  virtual bool SupportsStreamType(const content::MediaStreamType type,
+  virtual bool SupportsStreamType(content::WebContents* web_contents,
+                                  const content::MediaStreamType type,
                                   const extensions::Extension* extension) = 0;
   // Check media access permission. |extension| is set to NULL if request was
   // made from a drive-by page.
   virtual bool CheckMediaAccessPermission(
       content::WebContents* web_contents,
       const GURL& security_origin,
       content::MediaStreamType type,
       const extensions::Extension* extension) = 0;
   // Process media access requests. |extension| is set to NULL if request was
   // made from a drive-by page.
   virtual void HandleRequest(content::WebContents* web_contents,
                              const content::MediaStreamRequest& request,
                              const content::MediaResponseCallback& callback,
                              const extensions::Extension* extension) = 0;
   // Update media request state. Called on UI thread.
   virtual void UpdateMediaRequestState(int render_process_id,
                                        int render_frame_id,
                                        int page_request_id,
                                        content::MediaStreamType stream_type,
                                        content::MediaRequestState state) {}
+
+ protected:
+  // Helper function for derived classes which takes in whether audio/video
+  // permissions are allowed and queries for the requested devices, running the
+  // callback with the appropriate device list and status.
+  static void CheckDevicesAndRunCallback(
+      content::WebContents* web_contents,
+      const content::MediaStreamRequest& request,
+      const content::MediaResponseCallback& callback,
+      bool audio_allowed,
+      bool video_allowed);
 };
 
 #endif  // CHROME_BROWSER_MEDIA_MEDIA_ACCESS_HANDLER_H_