Use WaitableEvents to wake up sync IPC waiting

ipc/BUILD.gn

 # Copyright (c) 2012 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.
 
 import("//build/config/nacl/config.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
 
 component("ipc") {
@@ skipping 58 matching lines @@
     "mach_port_attachment_mac.cc",
     "mach_port_attachment_mac.h",
     "mach_port_mac.cc",
     "mach_port_mac.h",
     "message_filter.cc",
     "message_filter.h",
     "message_filter_router.cc",
     "message_filter_router.h",
     "message_router.cc",
     "message_router.h",
-    "mojo_event.cc",
-    "mojo_event.h",
     "param_traits_log_macros.h",
     "param_traits_macros.h",
     "param_traits_read_macros.h",
     "param_traits_write_macros.h",
     "struct_constructor_macros.h",
     "struct_destructor_macros.h",
   ]
 
   if (is_nacl && !is_nacl_nonsfi) {
     sources -= [ "ipc_channel.cc" ]
@@ skipping 145 matching lines @@
       ":ipc",
     ]
     deps = [
       "//base",
       "//base/test:test_support",
       "//mojo/edk/test:test_support",
       "//testing/gtest",
     ]
   }
 }