content/ui[Android]: Remove ContextProviderFactory.

ui/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("//build/config/android/rules.gni")
 import("//testing/test.gni")
 
 assert(is_android)
 
 component("android") {
   output_name = "ui_android"
   sources = [
     "animation_utils.h",
-    "context_provider_factory.cc",
-    "context_provider_factory.h",
     "delegated_frame_host_android.cc",
     "delegated_frame_host_android.h",
     "display_android_manager.cc",
     "display_android_manager.h",
     "edge_effect.cc",
     "edge_effect.h",
     "edge_effect_base.cc",
     "edge_effect_base.h",
     "edge_effect_l.cc",
     "edge_effect_l.h",
@@ skipping 238 matching lines @@
     "//cc",
     "//cc:test_support",
     "//skia",
     "//testing/gmock",
     "//testing/gtest",
     "//ui/base",
     "//ui/gfx",
     "//ui/resources:ui_test_pak",
   ]
 }