[Presentation API / Media Router] Clean up default pres URL logic.

chrome/browser/media/router/render_frame_host_id.h

Index: chrome/browser/media/router/render_frame_host_id.h
diff --git a/chrome/browser/media/router/render_frame_host_id.h b/chrome/browser/media/router/render_frame_host_id.h
new file mode 100644
index 0000000000000000000000000000000000000000..d9fb005a8bbebd922827b6399aea2e74a440633d
--- /dev/null
+++ b/chrome/browser/media/router/render_frame_host_id.h
@@ -0,0 +1,16 @@
+// 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 CHROME_BROWSER_MEDIA_ROUTER_RENDER_FRAME_HOST_ID_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_RENDER_FRAME_HOST_ID_H_
+
+#include <utility>
+
+namespace media_router {
+
+using RenderFrameHostId = std::pair<int, int>;
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_RENDER_FRAME_HOST_ID_H_