Use WaitableEvents to wake up sync IPC waiting

ipc/ipc_channel_mojo_unittest.cc

 // 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.
 
 #include "ipc/ipc_channel_mojo.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
@@ skipping 652 matching lines @@
     proxy_->Init(std::move(factory), true);
   }
 
   IPC::ChannelProxy* proxy() { return proxy_.get(); }
 
  private:
   const bool for_server_;
 
   mojo::ScopedMessagePipeHandle handle_;
   base::Thread io_thread_;
+  base::WaitableEvent never_signaled_;
   std::unique_ptr<IPC::ChannelProxy> proxy_;
-  base::WaitableEvent never_signaled_;
 
   DISALLOW_COPY_AND_ASSIGN(ChannelProxyRunner);
 };
 
 class IPCChannelProxyMojoTest : public IPCChannelMojoTestBase {
  public:
   void Init(const std::string& client_name) {
     IPCChannelMojoTestBase::Init(client_name);
     runner_.reset(new ChannelProxyRunner(TakeHandle(), true));
   }
@@ skipping 778 matching lines @@
   Connect(&listener);
 
   base::RunLoop().Run();
 
   Close();
 }
 
 #endif  // OS_LINUX
 
 }  // namespace