Begin adding support for tab mirroring via the MediaStream audio/video capturing

chrome/browser/media/media_stream_devices_controller.h

 // Copyright (c) 2012 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_STREAM_DEVICES_CONTROLLER_H_
 #define CHROME_BROWSER_MEDIA_MEDIA_STREAM_DEVICES_CONTROLLER_H_
 
 #include <string>
 
 #include "content/public/browser/web_contents_delegate.h"
 
-class GURL;
 class Profile;
 
 class MediaStreamDevicesController {
  public:
   // TODO(xians): Use const content::MediaStreamRequest& instead of *.
   MediaStreamDevicesController(Profile* profile,
                                const content::MediaStreamRequest* request,
                                const content::MediaResponseCallback& callback);
 
   virtual ~MediaStreamDevicesController();
 
   // Public method to be called before creating the MediaStreamInfoBarDelegate.
   // This function will check the content settings exceptions and take the
   // corresponding action on exception which matches the request.
   bool DismissInfoBarAndTakeActionOnSettings();
 
   // Public methods to be called by MediaStreamInfoBarDelegate;
   bool has_audio() const { return has_audio_; }
   bool has_video() const { return has_video_; }
+  const std::string& GetSecurityOriginSpec() const;
   content::MediaStreamDevices GetAudioDevices() const;
   content::MediaStreamDevices GetVideoDevices() const;
-  const GURL& GetSecurityOrigin() const;
+  bool IsSafeToAlwaysAllowAudio() const;
+  bool IsSafeToAlwaysAllowVideo() const;
   void Accept(const std::string& audio_id,
               const std::string& video_id,
               bool always_allow);
   void Deny();
 
  private:
-  // Finds a device in the current request with the specified |id| and |type|,
-  // adds it to the |devices| array and also return the name of the device.
-  void AddDeviceWithId(content::MediaStreamDeviceType type,
-                       const std::string& id,
-                       content::MediaStreamDevices* devices,
-                       std::string* device_name);
+  // Used by the various helper methods below to filter an operation on devices
+  // of a particular type.
+  typedef bool (*FilterByDeviceTypeFunc)(content::MediaStreamDeviceType);
+
+  // Returns true if a secure scheme is being used by the origin AND only
+  // devices of the given |user_type| are present in the subset of devices
+  // selected by the |is_included| function.
+  bool IsSafeToAlwaysAllow(FilterByDeviceTypeFunc is_included,
+                           content::MediaStreamDeviceType user_type) const;
 
   // Returns true if the media section in content settings is set to
   // |CONTENT_SETTING_BLOCK|, otherwise returns false.
   bool IsMediaDeviceBlocked();
 
+  // NOTE on AlwaysAllowOrigin functionality: The rules only apply to user
+  // capture devices, and not tab mirroring (or other types).  Non-user capture
+  // devices are always denied an AlwaysAllowOrigin status because they refer to
+  // internal objects whose "IDs" might be re-used for different objects across
+  // browser sessions.
+
   // Returns true if request's origin is from internal objects like
   // chrome://URLs, otherwise returns false.
   bool ShouldAlwaysAllowOrigin();
 
   // Grants "always allow" exception for the origin to use the selected devices.
   void AlwaysAllowOriginAndDevices(const std::string& audio_device,
                                    const std::string& video_device);
 
   // Gets the respective "always allowed" devices for the origin in |request_|.
   // |audio_id| and |video_id| will be empty if there is no "always allowed"
   // device for the origin, or any of the devices is not listed on the devices
   // list in |request_|.
   void GetAlwaysAllowedDevices(std::string* audio_id,
                                std::string* video_id);
 
   std::string GetDeviceIdByName(content::MediaStreamDeviceType type,
                                 const std::string& name);
 
   std::string GetFirstDeviceId(content::MediaStreamDeviceType type);
 
+  // Copies all devices passing the |is_included| predicate to the given output
+  // container.
+  void FindSubsetOfDevices(FilterByDeviceTypeFunc is_included,
+                           content::MediaStreamDevices* out) const;
+
+  // Find the first device with the given |device_id| within the subset of
+  // devices passing the |is_included| predicate, or return NULL.
+  const content::MediaStreamDevice* FindFirstDeviceWithIdInSubset(
+      FilterByDeviceTypeFunc is_included,
+      const std::string& device_id) const;
+
   bool has_audio_;
   bool has_video_;
 
   // The owner of this class needs to make sure it does not outlive the profile.
   Profile* profile_;
 
   // The original request for access to devices.
   const content::MediaStreamRequest request_;
 
   // The callback that needs to be Run to notify WebRTC of whether access to
   // audio/video devices was granted or not.
   content::MediaResponseCallback callback_;
   DISALLOW_COPY_AND_ASSIGN(MediaStreamDevicesController);
 };
 
 #endif  // CHROME_BROWSER_MEDIA_MEDIA_STREAM_DEVICES_CONTROLLER_H_