Revert of Remove remote tree host and some related input and metro_driver code

win8/BUILD.gn

 # 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.
 
+source_set("metro_viewer_constants") {
+  sources = [
+    "viewer/metro_viewer_constants.cc",
+    "viewer/metro_viewer_constants.h",
+  ]
+}
+
+component("metro_viewer") {
+  sources = [
+    "viewer/metro_viewer_process_host.cc",
+    "viewer/metro_viewer_process_host.h",
+  ]
+
+  defines = [ "METRO_VIEWER_IMPLEMENTATION" ]
+
+  deps = [
+    ":metro_viewer_constants",
+    "//base",
+    "//ipc",
+    "//ui/aura",
+    "//ui/gfx",
+    "//ui/metro_viewer",
+  ]
+}
+
 source_set("test_support_win8") {
   sources = [
     "test/open_with_dialog_async.cc",
     "test/open_with_dialog_async.h",
     "test/open_with_dialog_controller.cc",
     "test/open_with_dialog_controller.h",
     "test/ui_automation_client.cc",
     "test/ui_automation_client.h",
   ]
 
@@ skipping 28 matching lines @@
     ":test_registrar_constants",
     "//base",
     "//build/config/sanitizers:deps",
 
     # Chrome is the default viewer process currently used by the tests.
     # TODO(robertshield): Investigate building a standalone metro viewer
     # process.
     "//chrome",
   ]
 }