[Chromecast] Turn CastContentWindow into an abstract interface.

chromecast/android/cast_metrics_helper_android.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 "chromecast/android/cast_metrics_helper_android.h"
-
-#include "chromecast/base/metrics/cast_metrics_helper.h"
-#include "jni/CastMetricsHelper_jni.h"
-
-using base::android::JavaParamRef;
-
-namespace chromecast {
-
-// static
-bool CastMetricsHelperAndroid::RegisterJni(JNIEnv* env) {
-  return RegisterNativesImpl(env);
-}
-
-void LogMediaPlay(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
-  metrics::CastMetricsHelper::GetInstance()->LogMediaPlay();
-}
-
-void LogMediaPause(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
-  metrics::CastMetricsHelper::GetInstance()->LogMediaPause();
-}
-
-}  // namespace chromecast