[MediaRouter] Add implementation of PresentationServiceDelegate

chrome/browser/media/router/presentation_helper.h

Index: chrome/browser/media/router/presentation_helper.h
diff --git a/chrome/browser/media/router/presentation_helper.h b/chrome/browser/media/router/presentation_helper.h
new file mode 100644
index 0000000000000000000000000000000000000000..d60eba27ceadb82cd47068388f118ec0182e23fb
--- /dev/null
+++ b/chrome/browser/media/router/presentation_helper.h
@@ -0,0 +1,17 @@
+// 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_PRESENTATION_HELPER_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_PRESENTATION_HELPER_H_
+
+#include <string>
+
+namespace media_router {
+
+// Returns true if |source| is a valid presentation URL.
+bool IsValidPresentationUrl(const std::string& url);
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_PRESENTATION_HELPER_H_