Fix various issues in RedirectToFileResourceHandler.

content/browser/loader/async_resource_handler.cc

Index: content/browser/loader/async_resource_handler.cc
diff --git a/content/browser/loader/async_resource_handler.cc b/content/browser/loader/async_resource_handler.cc
index 93d7e839aa2d7af1b4c1507a447fa018de89a180..5eb69ad724f044fafe40a03fa6c17313f82b9b09 100644
--- a/content/browser/loader/async_resource_handler.cc
+++ b/content/browser/loader/async_resource_handler.cc
@@ -197,6 +197,14 @@ bool AsyncResourceHandler::OnResponseStarted(int request_id,
             net::GetHostOrSpecFromURL(request_url))));
   }
 
+  // If the parent handler downloaded the resource to a file, grant the child
+  // read permissions on it.
+  if (!response->head.download_file_path.empty()) {
+    rdh_->RegisterDownloadedTempFile(
+        info->GetChildID(), info->GetRequestID(),
+        response->head.download_file_path);
+  }

[mmenke, 2014/01/16 16:43:26]

Sure you don't want to keep this in the RedirectToFileResourceHandler?  I'm a
little concerned about changes/fixes here not making it into the
SyncResourceHandler as well.

[davidben, 2014/01/29 21:41:50]

Well, keeping it in RedirectToFileResourceHandler keeps the RTFRH -> RDH
dependency, which is what made it difficult to unit test in the first place. The
previous version put it in the CreateTemporary implementation, but it seemed
doing it right before sending the file path to the renderer was more
appropriate. (Also this means the mocked out function doesn't need to tie back
to the RDH and care about that thing's lifetime.)

I've added a comment to the two copies. We may also be able to just remove
SyncResourceHandler's download_to_file support altogether. I couldn't find code
in Blink that cared about it. And I think the loadSynchronously codepaths never
read from the blob handle renderer-side, so if it did happen, it wouldn't work.
Added a TODO about getting rid of it.

+
   response->head.request_start = request()->creation_time();
   response->head.response_start = TimeTicks::Now();
   info->filter()->Send(new ResourceMsg_ReceivedResponse(request_id,