Remove handler from MessagePumpForIO::IOContext.

base/message_loop/message_loop_unittest.cc

 // Copyright 2013 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 <stddef.h>
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 432 matching lines @@
   char buffer_[48];
   MessageLoopForIO::IOContext context_;
   HANDLE signal_;
   win::ScopedHandle file_;
   bool wait_;
 };
 
 TestIOHandler::TestIOHandler(const wchar_t* name, HANDLE signal, bool wait)
     : signal_(signal), wait_(wait) {
   memset(buffer_, 0, sizeof(buffer_));
-  memset(&context_, 0, sizeof(context_));
-  context_.handler = this;
 
   file_.Set(CreateFile(name, GENERIC_READ, 0, NULL, OPEN_EXISTING,
                        FILE_FLAG_OVERLAPPED, NULL));
   EXPECT_TRUE(file_.IsValid());
 }
 
 void TestIOHandler::Init() {
   MessageLoopForIO::current()->RegisterIOHandler(file_.Get(), this);
 
   DWORD read;
@@ skipping 507 matching lines @@
   // already has another active loop. This happens when thread creation fails.
   MessageLoop loop;
   std::unique_ptr<MessageLoop> unbound_loop(MessageLoop::CreateUnbound(
       MessageLoop::TYPE_DEFAULT, MessageLoop::MessagePumpFactoryCallback()));
   unbound_loop.reset();
   EXPECT_EQ(&loop, MessageLoop::current());
   EXPECT_EQ(loop.task_runner(), ThreadTaskRunnerHandle::Get());
 }
 
 }  // namespace base