Revert "Use AlertDialog for MediaRouteControllerDialog"

This reverts commit 001d51496d.

Background: To just inherit AlertDialog, the content view should include
a title as we do in support library (AlertDialog uses NO_TITLE feature),
but up-streaming support library implementation to the framework at this
point might cause more issues. Verified that the narrow dialog issue
(b/22044600) does not happen in the framework implementation regardless of
whether it uses AlertDialog or not.

Bug: 22286869
Change-Id: Ic2554cc9e683beff29d1deee91945c1dace83ab1

core/java/com/android/internal/app/MediaRouteControllerDialog.java

@@ -18,7 +18,7 @@ package com.android.internal.app;
 
 import com.android.internal.R;
 
-import android.app.AlertDialog;
+import android.app.Dialog;
 import android.app.MediaRouteActionProvider;
 import android.app.MediaRouteButton;
 import android.content.Context;
@@ -46,7 +46,7 @@ import android.widget.SeekBar;
  *
  * TODO: Move this back into the API, as in the support library media router.
  */
-public class MediaRouteControllerDialog extends AlertDialog {
+public class MediaRouteControllerDialog extends Dialog {
     // Time to wait before updating the volume when the user lets go of the seek bar
     // to allow the route provider time to propagate the change and publish a new
     // route descriptor.
@@ -134,6 +134,8 @@ public class MediaRouteControllerDialog extends AlertDialog {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
+        getWindow().requestFeature(Window.FEATURE_LEFT_ICON);
+
         setContentView(R.layout.media_route_controller_dialog);
 
         mVolumeLayout = (LinearLayout)findViewById(R.id.media_route_volume_layout);