Only double the buffer when AsyncResourceHandler's caller fill the buffer.

chrome/browser/renderer_host/async_resource_handler.h

 // 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.
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_ASYNC_RESOURCE_HANDLER_H_
 #define CHROME_BROWSER_RENDERER_HOST_ASYNC_RESOURCE_HANDLER_H_
 
 #include <string>
 
 #include "base/process.h"
@@ skipping 28 matching lines @@
   static void GlobalCleanup();
 
  private:
   scoped_refptr<SharedIOBuffer> read_buffer_;
   ResourceDispatcherHost::Receiver* receiver_;
   int process_id_;
   int routing_id_;
   base::ProcessHandle process_handle_;
   ResourceDispatcherHost* rdh_;
 
-  // We exponentially grow the size of the buffer allocated. On the first
-  // OnWillRead() call, we allocate a buffer of 32k and double it on each
-  // subsequent call, up to a maximum size of 512k. |next_buffer_size_| is the
-  // size of the buffer to be allocated on the next OnWillRead() call.
+  // |next_buffer_size_| is the size of the buffer to be allocated on the next
+  // OnWillRead() call.  We exponentially grow the size of the buffer allocated
+  // when our owner fills our buffers. On the first OnWillRead() call, we
+  // allocate a buffer of 32k and double it in OnReadCompleted() if the buffer
+  // was filled, up to a maximum size of 512k.
   int next_buffer_size_;
 
   DISALLOW_COPY_AND_ASSIGN(AsyncResourceHandler);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_ASYNC_RESOURCE_HANDLER_H_