[Cast,Android] Replace custom MediaController with android.widget.MediaController.

third_party/android_media/BUILD.gn

Index: third_party/android_media/BUILD.gn
diff --git a/third_party/android_media/BUILD.gn b/third_party/android_media/BUILD.gn
deleted file mode 100644
index a4a375ae8764a8fc327958bd36987a7b1454033f..0000000000000000000000000000000000000000
--- a/third_party/android_media/BUILD.gn
+++ /dev/null
@@ -1,26 +0,0 @@
-# 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("//build/config/android/rules.gni")
-
-assert(is_android)
-
-android_resources("android_media_resources") {
-  custom_package = "org.chromium.third_party.android.media"
-  resource_dirs = [ "java/res" ]
-  deps = [
-    "//third_party/android_tools:android_support_v7_appcompat_java",
-    "//third_party/android_tools:android_support_v7_mediarouter_java",
-  ]
-}
-
-android_library("android_media_java") {
-  java_files =
-      [ "java/src/org/chromium/third_party/android/media/MediaController.java" ]
-  deps = [
-    ":android_media_resources",
-    "//third_party/android_tools:android_support_v7_appcompat_java",
-    "//third_party/android_tools:android_support_v7_mediarouter_java",
-  ]
-}