Implement basic mojo Permission service and use it for Geolocation.

content/browser/permissions/permission_service_impl.h

+// Copyright 2014 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.
+
+#include "base/id_map.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "content/browser/permissions/permission_service_context.h"
+#include "content/common/permission_service.mojom.h"
+#include "content/public/browser/permission_type.h"
+
+#ifndef CONTENT_BROWSER_PERMISSIONS_PERMISSION_SERVICE_IMPL_H_
+#define CONTENT_BROWSER_PERMISSIONS_PERMISSION_SERVICE_IMPL_H_
+
+namespace content {
+
+// Implements the PermissionService Mojo interface.

[nasko, 2014/11/13 23:57:38]

For devs like me, who aren't familiar with Mojo semantics, it will be useful to
put a bit more information about lifetime of this object and relationship to
other concepts such as process/page/frame.

[mlamouri (slow - plz ping), 2014/11/14 00:16:33]

Acknowledged.

+class PermissionServiceImpl : public mojo::InterfaceImpl<PermissionService> {
+ public:
+  static void Create(scoped_ptr<PermissionServiceContext> context,
+                     mojo::InterfaceRequest<PermissionService> request);
+
+ protected:
+  friend PermissionServiceContext;
+
+  // Clear pending permissions associated with a given frame and request the
+  // browser to cancel the permission requests.
+  // This has to be called by the PermissionServiceContext.
+  void CancelPendingRequests();
+
+ private:
+  PermissionServiceImpl(scoped_ptr<PermissionServiceContext> context);
+  virtual ~PermissionServiceImpl();
+
+  // PermissionService:
+  void RequestPermission(
+      PermissionPtr permission,
+      const mojo::String& origin,
+      const mojo::Callback<void(PermissionStatus)>& callback) override;
+  void RevokePermission(
+      PermissionPtr permission,
+      const mojo::String& origin,
+      const mojo::Callback<void(PermissionStatus)>& callback) override;
+  void HasPermission(
+      PermissionPtr permission,
+      const mojo::String& origin,
+      const mojo::Callback<void(PermissionStatus)>& callback) override;
+  void StartObserving(
+      PermissionPtr permission,
+      const mojo::String& origin) override;
+  void StopObserving(
+      PermissionPtr permission,
+      const mojo::String& origin) override;
+
+  void OnRequestPermissionResponse(
+    const mojo::Callback<void(PermissionStatus)>& callback,
+    int request_id,
+    bool allowed);
+
+  struct PendingRequest {
+    PendingRequest(PermissionType permission, const GURL& origin);
+    PermissionType permission;
+    GURL origin;
+  };
+
+  typedef IDMap<PendingRequest, IDMapOwnPointer> RequestsMap;
+  RequestsMap pending_requests_;
+
+  scoped_ptr<PermissionServiceContext> context_;
+
+  base::WeakPtrFactory<PermissionServiceImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PermissionServiceImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_PERMISSIONS_PERMISSION_SERVICE_IMPL_H_