move file access permission logic to DownloadResourceThrottle

chrome/browser/download/download_request_limiter.h

Index: chrome/browser/download/download_request_limiter.h
diff --git a/chrome/browser/download/download_request_limiter.h b/chrome/browser/download/download_request_limiter.h
index 57a66bc93a0058f23ceea3550158122c9e5b3c32..8980940f46ddcddddc0bdf4b30ccede1c0fea059 100644
--- a/chrome/browser/download/download_request_limiter.h
+++ b/chrome/browser/download/download_request_limiter.h
@@ -181,13 +181,12 @@ class DownloadRequestLimiter
   // anyway.
   DownloadStatus GetDownloadStatus(content::WebContents* tab);
 
-  // Updates the state of the page as necessary and notifies the callback.
-  // WARNING: both this call and the callback are invoked on the io thread.
-  void CanDownloadOnIOThread(int render_process_host_id,
-                             int render_view_id,
-                             const GURL& url,
-                             const std::string& request_method,
-                             const Callback& callback);
+  // Check if download can proceed and notifies the callback on UI thread.
+  void CanDownload(int render_process_host_id,
+                   int render_view_id,
+                   const GURL& url,
+                   const std::string& request_method,
+                   const Callback& callback);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(DownloadTest, DownloadResourceThrottleCancels);
@@ -209,14 +208,6 @@ class DownloadRequestLimiter
       content::WebContents* originating_web_contents,
       bool create);
 
-  // CanDownloadOnIOThread invokes this on the UI thread. This determines the
-  // tab and invokes CanDownloadImpl.
-  void CanDownload(int render_process_host_id,
-                   int render_view_id,
-                   const GURL& url,
-                   const std::string& request_method,
-                   const Callback& callback);
-
   // Does the work of updating the download status on the UI thread and
   // potentially prompting the user.
   void CanDownloadImpl(content::WebContents* originating_contents,