Move gtest/gmock BUILD.gn files to main tree.

testing/gmock/BUILD.gn

 # Copyright (c) 2013 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.
 
 config("gmock_config") {
   # Gmock headers need to be able to find themselves.
   include_dirs = [ "include" ]
 }
 
 static_library("gmock") {
@@ skipping 20 matching lines @@
     "gmock_mutant.h",  # gMock helpers
   ]
 
   # This project includes some stuff form gtest's guts.
   include_dirs = [ "../gtest/include" ]
 
   direct_dependent_configs = [
     ":gmock_config",
     "//testing/gtest:gtest_config",
   ]
+  if (is_win) {
+    all_dependent_configs += [
+      "//build/config/win:disable_unused_variable_warning",
+    ]
+  }
 }
 
 static_library("gmock_main") {
   sources = [ "src/gmock_main.cc" ]
   deps = [ ":gmock" ]
 }