Factor out dependncy on download throttling from core download code.

chrome/browser/download/download_throttling_resource_handler.h

 // Copyright (c) 2011 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_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_
-#define CHROME_BROWSER_RENDERER_HOST_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_
+#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_
 #pragma once
 
 #include <string>
 
 #include "chrome/browser/download/download_request_limiter.h"
 #include "content/browser/renderer_host/resource_handler.h"
 #include "googleurl/src/gurl.h"
 
 class DownloadResourceHandler;
 class ResourceDispatcherHost;
 
 namespace net {
 class URLRequest;
 }  // namespace net
 
 // DownloadThrottlingResourceHandler is used to determine if a download should
 // be allowed. When a DownloadThrottlingResourceHandler is created it pauses the
 // download and asks the DownloadRequestLimiter if the download should be
 // allowed. The DownloadRequestLimiter notifies us asynchronously as to whether
 // the download is allowed or not. If the download is allowed the request is
-// resumed, a DownloadResourceHandler is created and all EventHandler methods
-// are delegated to it. If the download is not allowed the request is canceled.
+// resumed, all EventHandler methods are delegated to it to the original
+// handler. If the download is not allowed the request is canceled.
 
 class DownloadThrottlingResourceHandler
     : public ResourceHandler,
       public DownloadRequestLimiter::Callback {
  public:
-  DownloadThrottlingResourceHandler(ResourceDispatcherHost* host,
+  DownloadThrottlingResourceHandler(ResourceHandler* next_handler,
+                                    ResourceDispatcherHost* host,
+                                    DownloadRequestLimiter* limiter,
                                     net::URLRequest* request,
                                     const GURL& url,
                                     int render_process_host_id,
                                     int render_view_id,
                                     int request_id,
                                     bool in_complete);
 
   // ResourceHanlder implementation:
   virtual bool OnUploadProgress(int request_id,
                                 uint64 position,
@@ skipping 19 matching lines @@
 
   void CopyTmpBufferToDownloadHandler();
 
   ResourceDispatcherHost* host_;
   net::URLRequest* request_;
   GURL url_;
   int render_process_host_id_;
   int render_view_id_;
   int request_id_;
 
-  // Handles the actual download. This is only created if the download is
-  // allowed to continue.
-  scoped_refptr<DownloadResourceHandler> download_handler_;
+  // The original handler.
+  scoped_refptr<ResourceHandler> next_handler_;
+
+  // Set to true when we know that the request is allowed to start.
+  bool request_allowed_;
 
   // Response supplied to OnResponseStarted. Only non-null if OnResponseStarted
   // is invoked.
   scoped_refptr<ResourceResponse> response_;
 
   // If we're created by way of BufferedEventHandler we'll get one request for
   // a buffer. This is that buffer.
   scoped_refptr<net::IOBuffer> tmp_buffer_;
   int tmp_buffer_length_;
 
   // If true the next call to OnReadCompleted is ignored. This is used if we're
   // paused during a call to OnReadCompleted. Pausing during OnReadCompleted
   // results in two calls to OnReadCompleted for the same data. This make sure
   // we ignore one of them.
   bool ignore_on_read_complete_;
 
   // Have we received OnRequestClosed()?  If so, we shouldn't act on
   // CancelDownload()/ContinueDownload().
   bool request_closed_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadThrottlingResourceHandler);
 };
 
-#endif  // CHROME_BROWSER_RENDERER_HOST_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_
+#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_