Implements a monitor to watch for the browser hanging.

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",
     "exit_code_watcher_win.cc",
     "exit_code_watcher_win.h",
     "exit_funnel_win.cc",
     "exit_funnel_win.h",
+    "window_hang_monitor_win.cc",
+    "window_hang_monitor_win.h",
   ]
   deps = [
     "//base",
   ]
 }
 
 source_set("browser_watcher_client") {
   sources = [
     "watcher_client_win.cc",
     "watcher_client_win.h",
     "watcher_metrics_provider_win.cc",
     "watcher_metrics_provider_win.h",
   ]
   deps = [
     "//base",
   ]
 }
 
 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",
+    "window_hang_monitor_win_unittest.cc",
   ]
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
   deps = [
     ":browser_watcher",
     ":browser_watcher_client",
     "//testing/gtest",
   ]
 }