Add more size_t -> int warning fixes for the win x64 GN build.

components/browser_watcher/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.
 
 source_set("browser_watcher") {
   # This is a separate lib to minimize the dependencies for its
   # hosting binary "chrome_watcher.dll".
   sources = [
     "endsession_watcher_window_win.cc",
     "endsession_watcher_window_win.h",
@@ skipping 21 matching lines @@
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "endsession_watcher_window_win_unittest.cc",
     "exit_code_watcher_win_unittest.cc",
     "exit_funnel_win_unittest.cc",
     "watcher_client_win_unittest.cc",
     "watcher_metrics_provider_win_unittest.cc",
   ]
+  configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
   deps = [
     ":browser_watcher",
     ":browser_watcher_client",
     "//testing/gtest",
   ]
 }