Factor out dependncy on download throttling from core download code.

chrome/browser/renderer_host/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_
-#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.
-
-class DownloadThrottlingResourceHandler
-    : public ResourceHandler,
-      public DownloadRequestLimiter::Callback {
- public:
-  DownloadThrottlingResourceHandler(ResourceDispatcherHost* host,
-                                    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,
-                                uint64 size);
-  virtual bool OnRequestRedirected(int request_id, const GURL& url,
-                                   ResourceResponse* response, bool* defer);
-  virtual bool OnResponseStarted(int request_id, ResourceResponse* response);
-  virtual bool OnWillStart(int request_id, const GURL& url, bool* defer);
-  virtual bool OnWillRead(int request_id, net::IOBuffer** buf, int* buf_size,
-                          int min_size);
-  virtual bool OnReadCompleted(int request_id, int* bytes_read);
-  virtual bool OnResponseCompleted(int request_id,
-                                   const net::URLRequestStatus& status,
-                                   const std::string& security_info);
-  virtual void OnRequestClosed();
-
-  // DownloadRequestLimiter::Callback implementation:
-  virtual void CancelDownload();
-  virtual void ContinueDownload();
-
- private:
-  virtual ~DownloadThrottlingResourceHandler();
-
-  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_;
-
-  // 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_