Plumb suggested_filename through OpenURL path

If we navigate to a blob URL, we'll use OpenURL() to initiate the
navigation. In order to correctly handle <a download>, we'll also need
to plumb the download attribute's content (aka suggested filename)
through

BUG=798705
[email protected]

Change-Id: I3e86c67efacc1657786a1ea23ab765802bef3297
Reviewed-on: https://chromium-review.googlesource.com/848897
Reviewed-by: Mike West <[email protected]>
Reviewed-by: Camille Lamy <[email protected]>
Commit-Queue: Jochen Eisinger <[email protected]>
Cr-Commit-Position: refs/heads/master@{#528910}
diff --git a/content/browser/frame_host/navigator_impl.h b/content/browser/frame_host/navigator_impl.h
index 4c198a2..96cca8b0 100644
--- a/content/browser/frame_host/navigator_impl.h
+++ b/content/browser/frame_host/navigator_impl.h
@@ -74,7 +74,8 @@
       WindowOpenDisposition disposition,
       bool should_replace_current_entry,
       bool user_gesture,
-      blink::WebTriggeringEventInfo triggering_event_info) override;
+      blink::WebTriggeringEventInfo triggering_event_info,
+      const base::Optional<std::string>& suggested_filename) override;
   void RequestTransferURL(RenderFrameHostImpl* render_frame_host,
                           const GURL& url,
                           SiteInstance* source_site_instance,