Introduce chrome.displaySource API

extensions/browser/api/display_source/display_source_event_router.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 EXTENSIONS_BROWSER_API_DISPLAY_SOURCE_DISPLAY_SOURCE_EVENT_ROUTER_H_
+#define EXTENSIONS_BROWSER_API_DISPLAY_SOURCE_DISPLAY_SOURCE_EVENT_ROUTER_H_
+
+#include "base/macros.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "extensions/browser/event_router.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace extensions {
+
+// Observe listeners to 'onSinksUpdated' events.
+class DisplaySourceEventRouter : public KeyedService,
+                                 public EventRouter::Observer {
+ public:
+  static DisplaySourceEventRouter* Create(
+      content::BrowserContext* browser_context);
+
+ protected:
+  DisplaySourceEventRouter() = default;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DisplaySourceEventRouter);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_DISPLAY_SOURCE_DISPLAY_SOURCE_EVENT_ROUTER_H_