Implement Permissions.query() and static PermissionStatus.

public/platform/modules/permissions/WebPermissionClient.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 WebPermissionClient_h
+#define WebPermissionClient_h
+
+#include "public/platform/WebCallbacks.h"
+#include "public/platform/modules/permissions/WebPermissionStatus.h"
+#include "public/platform/modules/permissions/WebPermissionType.h"
+
+namespace blink {
+
+using WebPermissionQueryCallback = WebCallbacks<WebPermissionStatus, void>;
+
+class WebURL;
+
+// This client is expected to do general permission handling. From simple
+// permission query to requesting new permissions.
+class WebPermissionClient {
+public:
+    // Query the permission status of a given origin for a specific permission.
+    virtual void queryPermission(WebPermissionType, const WebURL&, WebPermissionQueryCallback*) = 0;
+
+protected:
+    virtual ~WebPermissionClient() { }
+};
+
+} // namespace blink
+
+#endif // WebPermissionClient_h