[Chromecast] Turn CastContentWindow into an abstract interface.

chromecast/browser/android/cast_metrics_helper_android.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 CHROMECAST_ANDROID_CAST_METRICS_HELPER_ANDROID_H_
-#define CHROMECAST_ANDROID_CAST_METRICS_HELPER_ANDROID_H_
+#ifndef CHROMECAST_BROWSER_ANDROID_CAST_METRICS_HELPER_ANDROID_H_
+#define CHROMECAST_BROWSER_ANDROID_CAST_METRICS_HELPER_ANDROID_H_
 
 #include <jni.h>
 #include <vector>
 
 #include "base/macros.h"
 
 namespace chromecast {
-
+namespace shell {
 class CastMetricsHelperAndroid {
  public:
   // Registers the JNI methods for CastMetricsHelperAndroid.
   static bool RegisterJni(JNIEnv* env);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(CastMetricsHelperAndroid);
 };
 
+}  // namespace shell
 }  // namespace chromecast
 
-#endif  // CHROMECAST_ANDROID_CAST_METRICS_HELPER_ANDROID_H_
+#endif  // CHROMECAST_BROWSER_ANDROID_CAST_METRICS_HELPER_ANDROID_H_