Fixed all unused-variable Clang warnings on Windows.

ipc/ipc_channel_win.cc

 // 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.
 
 #include "ipc/ipc_channel_win.h"
 
 #include <windows.h>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 50 matching lines @@
 
   if (input_state_.is_pending || output_state_.is_pending)
     CancelIo(pipe_.Get());
 
   // Closing the handle at this point prevents us from issuing more requests
   // form OnIOCompleted().
   if (pipe_.IsValid())
     pipe_.Close();
 
   // Make sure all IO has completed.
-  base::Time start = base::Time::Now();
   while (input_state_.is_pending || output_state_.is_pending) {
     base::MessageLoopForIO::current()->WaitForIOCompletion(INFINITE, this);
   }
 
   while (!output_queue_.empty()) {
     Message* m = output_queue_.front();
     output_queue_.pop();
     delete m;
   }
 }
@@ skipping 428 matching lines @@
   int secret;
   do {  // Guarantee we get a non-zero value.
     secret = base::RandInt(0, std::numeric_limits<int>::max());
   } while (secret == 0);
 
   id.append(GenerateUniqueRandomChannelID());
   return id.append(base::StringPrintf("\\%d", secret));
 }
 
 }  // namespace IPC