Fix resize with --enable-threaded-compositing

BUG=https://bugs.webkit.org/show_bug.cgi?id=74290
TEST=chrome --enable-threaded-compositing


Review URL: http://codereview.chromium.org/8912002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114260 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/render_widget.cc

@@ -1044,7 +1044,7 @@ void RenderWidget::didCompleteSwapBuffers() {
   params.plugin_window_moves.swap(plugin_window_moves_);
   params.flags = next_paint_flags_;
   params.scroll_offset = GetScrollOffset();
-  update_reply_pending_ = true;
+  params.needs_ack = false;
 
   Send(new ViewHostMsg_UpdateRect(routing_id_, params));
   next_paint_flags_ = 0;