Fix a memory leak on the async resource handler.

chrome/browser/renderer_host/async_resource_handler.cc

 // Copyright (c) 2006-2008 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 "chrome/browser/renderer_host/async_resource_handler.h"
 
 #include "base/process.h"
 #include "net/base/io_buffer.h"
 
 SharedIOBuffer* AsyncResourceHandler::spare_read_buffer_;
 
 // Our version of IOBuffer that uses shared memory.
 class SharedIOBuffer : public net::IOBuffer {
  public:
-  SharedIOBuffer(int buffer_size) : net::IOBuffer(NULL), ok_(false) {
+  SharedIOBuffer(int buffer_size) : net::IOBuffer(), ok_(false) {
     if (shared_memory_.Create(std::wstring(), false, false, buffer_size) &&
         shared_memory_.Map(buffer_size)) {
       ok_ = true;
       data_ = reinterpret_cast<char*>(shared_memory_.memory());
     }
   }
   ~SharedIOBuffer() {
     data_ = NULL;
   }
 
@@ skipping 97 matching lines @@
   } else if (read_buffer_.get()) {
     read_buffer_.swap(&spare_read_buffer_);
   }
   return true;
 }
 
 // static
 void AsyncResourceHandler::GlobalCleanup() {
   spare_read_buffer_ = NULL;
 }