media: Add mojo MediaPermission service

content/browser/media/media_permission_impl.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_PERMISSION_IMPL_H_
+#define CONTENT_BROWSER_MEDIA_MEDIA_PERMISSION_IMPL_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "content/common/permission_service.mojom.h"
+#include "media/mojo/interfaces/media_permission.mojom.h"
+#include "mojo/public/cpp/bindings/interface_request.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+namespace media {
+class MediaPermission;
+}
+
+namespace content {
+
+class PermissionServiceContext;
+
+// An media::interfaces::MediaPermission implementation based on
+// media::MediaPermission.
+class MediaPermissionImpl : public media::interfaces::MediaPermission {
+ public:
+  static void Create(PermissionServiceContext* permission_service_context,

[xhwang, 2016/03/30 07:11:34]

rockot: We'll use PermissionService in the same browser process to implement the
media::interfaces::MediaPermission service. When we use a service in the same
process, I assume we'll still go through all the serialization. Is there any
concern over this use pattern? In this case the calls are infrequent and very
light-weighted, so I don't think performance is a concern.

+                     media::interfaces::MediaPermissionRequest request);
+
+  MediaPermissionImpl(PermissionServiceContext* permission_service_context,
+                      media::interfaces::MediaPermissionRequest request);
+  ~MediaPermissionImpl() override;
+
+  // media::interfaces::MediaPermission implementation.
+  void HasPermission(MediaPermission::Type type,
+                     const mojo::String& security_origin,
+                     const HasPermissionCallback& callback) final;
+  void RequestPermission(MediaPermission::Type type,
+                         const mojo::String& security_origin,
+                         const RequestPermissionCallback& callback) final;
+
+ private:
+  // Callback to get interface::MediaPermission service.
+  void GetMediaPermissionService(mojom::PermissionServiceRequest request);
+
+  // Helper function to lazily initialize |media_permission_| and return it.
+  media::MediaPermission* GetMediaPermission();
+
+  // Callback for HasPermission() and RequestPermission();
+  void OnPermissionStatus(const mojo::Callback<void(bool)>& callback,
+                          bool success);
+
+  PermissionServiceContext* permission_service_context_;
+  mojo::StrongBinding<media::interfaces::MediaPermission> binding_;
+  scoped_ptr<media::MediaPermission> media_permission_;
+  base::WeakPtrFactory<MediaPermissionImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaPermissionImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_MEDIA_PERMISSION_IMPL_H_