ash: Refactor touch hud drawing to ash/touch_hud as a separate component.

ash/touch_hud/BUILD.gn

 # Copyright 2016 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.
 
-source_set("ios") {
+import("//build/config/ui.gni")
+
+source_set("touch_hud") {
   sources = [
-    "favicon_url_util.cc",
-    "favicon_url_util.h",
-    "web_favicon_driver.h",
-    "web_favicon_driver.mm",
+    "touch_hud_renderer.cc",
+    "touch_hud_renderer.h",
   ]
+
   deps = [
     "//base",
-    "//components/favicon/core",
-    "//components/favicon_base",
-    "//ios/web",
+    "//skia",
+    "//ui/events",
     "//ui/gfx",
+    "//ui/views",
   ]
+
+  if (is_chromeos) {
+    deps += [ "//chromeos" ]
+  }
 }