[Chromecast] Turn CastContentWindow into an abstract interface.

chromecast/android/BUILD.gn

 # 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.
 
 import("//chromecast/chromecast.gni")
 
 # These targets shall only be referenced on Android builds.
 assert(is_android)
 
 # This source_set should only contain headers for internal code. These must be
 # built separately from public stub implementations of this code to keep the
 # dependency tree clean.
 source_set("platform_jni_loader") {
   sources = [
     "platform_jni_loader.h",
   ]
 }
 
 shared_library("libcast_shell_android") {
   sources = [
     "//chromecast/app/android/cast_jni_loader.cc",
     "cast_jni_registrar.cc",
     "cast_jni_registrar.h",
-    "cast_metrics_helper_android.cc",
-    "cast_metrics_helper_android.h",
   ]
 
   deps = [
     ":platform_jni_loader",
     "//base",
     "//chromecast:cast_shell_lib",
     "//chromecast/app",
     "//chromecast/app:cast_crash_client",
     "//chromecast/base",
     "//chromecast/base:cast_sys_info",
     "//chromecast/base:jni_headers",
     "//chromecast/base/metrics",
     "//chromecast/browser",
-    "//chromecast/browser:jni_headers",
     "//content/public/app:both",
     "//content/public/browser",
     "//skia",
   ]
 
   if (chromecast_branding == "public") {
     sources += [ "platform_jni_loader_stub.cc" ]
   }
 }