Don't forget to free the callbacks!

webkit/glue/image_resource_fetcher.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 "webkit/glue/image_resource_fetcher.h"
 
 #include "base/gfx/size.h"
 #include "webkit/glue/image_decoder.h"
 #include "webkit/glue/webframe.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ skipping 27 matching lines @@
   if (!response.isNull() && response.httpStatusCode() == 200) {
     // Request succeeded, try to convert it to an image.
     ImageDecoder decoder(gfx::Size(image_size_, image_size_));
     bitmap = decoder.Decode(
         reinterpret_cast<const unsigned char*>(data.data()), data.size());
   } // else case:
     // If we get here, it means no image from server or couldn't decode the
     // response as an image. The delegate will see a null image, indicating
     // that an error occurred.
   callback_->Run(this, bitmap);
+  callback_.reset();
 }
 
 }  // namespace webkit_glue