Upstream Chrome for Android Cast.

chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControlV16.java

Index: chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControlV16.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControlV16.java b/chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControlV16.java
new file mode 100644
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+++ b/chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControlV16.java
@@ -0,0 +1,37 @@
+// Copyright 2014 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.
+
+package org.chromium.chrome.browser.media.remote;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.os.Build;
+import android.support.v7.media.MediaRouter;
+
+/**
+ * An implementation of {@link LockScreenTransportControl} targeting platforms with an API greater
+ * than 15. Extends {@link LockScreenTransportControlV14}, adding support for remote volume control.
+ */
+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
+class LockScreenTransportControlV16 extends LockScreenTransportControlV14 {
+
+    private final MediaRouter mMediaRouter;
+
+    LockScreenTransportControlV16(Context context) {
+        super(context);
+        mMediaRouter = MediaRouter.getInstance(context);
+    }
+
+    @Override
+    protected void register() {
+        super.register();
+        mMediaRouter.addRemoteControlClient(getRemoteControlClient());
+    }
+
+    @Override
+    protected void unregister() {
+        mMediaRouter.removeRemoteControlClient(getRemoteControlClient());
+        super.unregister();
+    }
+}