Add Media Router Mojo impl code.

chrome/browser/media/router/test_helper.cc

+// 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.
+
+#include "chrome/browser/media/router/test_helper.h"
+
+namespace media_router {
+
+MockMediaSinksObserver::MockMediaSinksObserver(MediaRouter* router,
+                                               const MediaSource& source)
+    : MediaSinksObserver(router, source) {
+}
+MockMediaSinksObserver::~MockMediaSinksObserver() {
+}

[Wez, 2015/05/20 23:37:50]

nit: } can appear immediately after { since this is a single-line declaration.

[imcheng (use chromium acct), 2015/05/21 19:28:53]

Actually, this is due to `git cl format`.

+
+MockMediaRoutesObserver::MockMediaRoutesObserver(MediaRouter* router)
+    : MediaRoutesObserver(router) {
+}
+MockMediaRoutesObserver::~MockMediaRoutesObserver() {
+}
+
+MockEventPageTracker::MockEventPageTracker() {
+}
+MockEventPageTracker::~MockEventPageTracker() {
+}
+
+}  // namespace media_router