Reland of [VSync Queue] Plug touch ack to gesture events and flush vsync queue if necessary

content/browser/renderer_host/ui_events_helper.h

Index: content/browser/renderer_host/ui_events_helper.h
diff --git a/content/browser/renderer_host/ui_events_helper.h b/content/browser/renderer_host/ui_events_helper.h
index b04a8d35dd5f089c4a43f9c4395c447a8a87a789..2123a2a26fd4d41193b7afcf90a509c4ff229c8c 100644
--- a/content/browser/renderer_host/ui_events_helper.h
+++ b/content/browser/renderer_host/ui_events_helper.h
@@ -10,6 +10,7 @@
 
 #include "content/browser/renderer_host/event_with_latency_info.h"
 #include "content/common/content_export.h"
+#include "content/common/input/input_event_ack_state.h"
 
 namespace ui {
 class TouchEvent;
@@ -37,6 +38,10 @@
     std::vector<std::unique_ptr<ui::TouchEvent>>* list,
     TouchEventCoordinateSystem coordinate_system);
 
+// Utility to map the event ack state from the renderer, returns true if the
+// event could be handled non-blocking.
+bool InputEventAckStateIsSetNonBlocking(InputEventAckState);
+
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_UI_EVENTS_HELPER_H_