Fix an issue that we didn't clean url request properly.

content/browser/download/download_job.h

Index: content/browser/download/download_job.h
diff --git a/content/browser/download/download_job.h b/content/browser/download/download_job.h
index d4db0ece9889c4b710066fa2b0b20231f55cc4fa..0998cea50072d471842b1fe4fad076d297fce400 100644
--- a/content/browser/download/download_job.h
+++ b/content/browser/download/download_job.h
@@ -43,6 +43,10 @@ class CONTENT_EXPORT DownloadJob {
   // Returns whether the download uses parallel requests.
   virtual bool UsesParallelRequests() const;
 
+  // Cancel a particular request starts from |offset|, while the download is not
+  // canceled. Used in parallel download.
+  virtual void CancelRequestWithOffset(int64_t offset);
+
  protected:
   void StartDownload() const;
   void Interrupt(DownloadInterruptReason reason);