Add flag to specify if explicitly requested download is from web.

This allows interposing the DownloadResourceThrottle on all web 
downloads, not just those occuring because of navigations.

BUG=127522
[email protected]
TEST=Retry example in referenced issue; look for throttling message.


Review URL: https://chromiumcodereview.appspot.com/10381122

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137137 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/browser/download/download_manager_impl.cc b/content/browser/download/download_manager_impl.cc
index dc655bf..cf9ae3a 100644
--- a/content/browser/download/download_manager_impl.cc
+++ b/content/browser/download/download_manager_impl.cc
@@ -83,6 +83,7 @@
   }
   resource_dispatcher_host->BeginDownload(
       request.Pass(),
+      params->content_initiated(),
       params->resource_context(),
       params->render_process_host_id(),
       params->render_view_host_routing_id(),