Modified cancel and interrupt processing to avoid race with history.

chrome/browser/download/download_request_handle.h

Index: chrome/browser/download/download_request_handle.h
diff --git a/chrome/browser/download/download_request_handle.h b/chrome/browser/download/download_request_handle.h
index e591cb80f166bdb262bd7cc87a194e95f1722ff2..00a40c70e87b1687a9e58058a7c0a47097beda44 100644
--- a/chrome/browser/download/download_request_handle.h
+++ b/chrome/browser/download/download_request_handle.h
@@ -37,12 +37,16 @@ class DownloadRequestHandle {
   TabContents* GetTabContents() const;
   DownloadManager* GetDownloadManager() const;
 
-  // Pause or resume the matching URL request.
-  void PauseRequest();
-  void ResumeRequest();
+  // Pause or resume the matching URL request.  Note that while these
+  // do not modify the DownloadRequestHandle, they do modify the
+  // request the handle refers to.
+  void PauseRequest() const;
+  void ResumeRequest() const;
 
-  // Cancel the request
-  void CancelRequest();
+  // Cancel the request.  Note that while this does not
+  // modify the DownloadRequestHandle, it does modify the
+  // request the handle refers to.
+  void CancelRequest() const;
 
   std::string DebugString() const;