Modified cancel and interrupt processing to avoid race with history.

chrome/browser/download/download_request_handle.cc

 // 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.
 
 #include "chrome/browser/download/download_request_handle.h"
 
 #include "base/stringprintf.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_util.h"
 #include "content/browser/browser_thread.h"
@@ skipping 50 matching lines @@
   if (!contents)
     return NULL;
 
   Profile* profile = contents->profile();
   if (!profile)
     return NULL;
 
   return profile->GetDownloadManager();
 }
 
-void DownloadRequestHandle::PauseRequest() {
+void DownloadRequestHandle::PauseRequest() const {
   // The post is safe because ResourceDispatcherHost is guaranteed
   // to outlive the IO thread.
   if (rdh_) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         NewRunnableFunction(&ResourceDispatcherHostPauseRequest,
                             rdh_, child_id_, request_id_, true));
   }
 }
 
-void DownloadRequestHandle::ResumeRequest() {
+void DownloadRequestHandle::ResumeRequest() const {
   // The post is safe because ResourceDispatcherHost is guaranteed
   // to outlive the IO thread.
   if (rdh_) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         NewRunnableFunction(&ResourceDispatcherHostPauseRequest,
                             rdh_, child_id_, request_id_, false));
   }
 }
 
-void DownloadRequestHandle::CancelRequest() {
+void DownloadRequestHandle::CancelRequest() const {
   // The post is safe because ResourceDispatcherHost is guaranteed
   // to outlive the IO thread.
   if (rdh_) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         NewRunnableFunction(&ResourceDispatcherHostCancelRequest,
                             rdh_, child_id_, request_id_));
   }
 }
 
 std::string DownloadRequestHandle::DebugString() const {
   return base::StringPrintf("{"
                             " child_id = %d"
                             " render_view_id = %d"
                             " request_id = %d"
                             "}",
                             child_id_,
                             render_view_id_,
                             request_id_);
 }