Introduce MediaDevicesPermissionChecker.

content/browser/media/media_devices_permission_checker.h

+// Copyright 2016 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 CONTENT_BROWSER_MEDIA_MEDIA_DEVICES_PERMISSION_CHECKER_H_
+#define CONTENT_BROWSER_MEDIA_MEDIA_DEVICES_PERMISSION_CHECKER_H_
+
+#include <memory>
+
+#include "base/callback.h"
+#include "content/browser/renderer_host/media/media_devices_manager.h"
+#include "content/common/content_export.h"
+
+namespace url {
+class Origin;
+}
+
+namespace content {
+
+// This class provides various utility functions to check if a render frame
+// has permission to access media devices. Note that none of the methods
+// prompts the user to request permission.
+class CONTENT_EXPORT MediaDevicesPermissionChecker {
+ public:
+  MediaDevicesPermissionChecker();
+
+  // Checks if the origin |security_origin| associated to a render frame
+  // identified by |render_process_id| and |render_frame_id| is allowed to
+  // access the media device type |device_type|.
+  // This method must be called on the UI thread.
+  bool CheckPermissionOnUIThread(MediaDeviceType device_type,
+                                 int render_process_id,
+                                 int render_frame_id,
+                                 const url::Origin& security_origin);
+
+  // Checks if the origin |security_origin| associated to a render frame
+  // identified by |render_process_id| and |render_frame_id| is allowed to
+  // access the media device type |device_type|. The result is passed to
+  // |callback|.
+  // This method can be called on any thread. |callback| is fired on the same
+  // thread this method is called on.
+  void CheckPermission(MediaDeviceType device_type,
+                       int render_process_id,
+                       int render_frame_id,
+                       const url::Origin& security_origin,
+                       const base::Callback<void(bool)>& callback);
+
+  // Checks if the origin |security_origin| associated to a render frame
+  // identified by |render_process_id| and |render_frame_id| is allowed to
+  // access the media device types marked with a value of true in
+  // |requested_device_types|.  The result is indexed by MediaDeviceType.
+  // Entries in the result with a value of true for requested device types
+  // indicate that the frame has permission to access devices of the
+  // corresponding types.
+  // This method must be called on the UI thread.
+  MediaDevicesManager::BoolDeviceTypes CheckPermissionsOnUIThread(
+      MediaDevicesManager::BoolDeviceTypes requested_device_types,
+      int render_process_id,
+      int render_frame_id,
+      const url::Origin& security_origin);
+
+  // Checks if the origin |security_origin| associated to a render frame
+  // identified by |render_process_id| and |render_frame_id| is allowed to
+  // access the media device types marked with a value of true in
+  // |requested_device_types|. The result is passed to |callback|. The result is
+  // indexed by MediaDeviceType. Entries in the result with a value of true for
+  // requested  device types indicate that the frame has permission to access
+  // devices of the corresponding types.
+  // This method can be called on any thread. |callback| is fired on the same
+  // thread this method is called on.
+  void CheckPermissions(
+      MediaDevicesManager::BoolDeviceTypes requested_device_types,
+      int render_process_id,
+      int render_frame_id,
+      const url::Origin& security_origin,
+      const base::Callback<void(const MediaDevicesManager::BoolDeviceTypes&)>&
+          callback);
+
+  // Forces a specific value to be returned by the permission-checking functions
+  // for all device types. Use only for testing.
+  void OverridePermissionsForTesting(bool override_value);
+
+ private:
+  bool use_override_;
+  bool override_value_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_MEDIA_DEVICES_PERMISSION_CHECKER_H_