[chromecast] Pass media task runner to VideoPlaneController.

chromecast/graphics/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")
 import("//build/config/ui.gni")
 
 if (use_aura) {
   source_set("graphics") {
     sources = [
       "cast_screen.cc",
       "cast_screen.h",
     ]
 
     deps = [
+      "//chromecast/public",
       "//ui/aura",
       "//ui/gfx",
       "//ui/gfx/geometry",
     ]
   }
 }
 
 shared_library("libcast_graphics_1.0") {
   sources = [
     "cast_egl_platform_default.cc",
     "graphics_properties_default.cc",
     "osd_plane_default.cc",
   ]
 
   public_deps = [
     "//chromecast/public",
   ]
 
   deps = [
     "//base",
   ]
 }