Implement Gesture event hit testing/forwarding for OOPIF.

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 14364447b36ded0f60c9d568783b55c6f31a3078..5fb528ddd4e4a347f64f44725686d660b54d241b 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -1613,6 +1613,12 @@ void RenderWidgetHostViewMac::ProcessTouchEvent(
   render_widget_host_->ForwardTouchEventWithLatencyInfo(event, latency);
 }
 
+void RenderWidgetHostViewMac::ProcessGestureEvent(
+    const blink::WebGestureEvent& event,
+    const ui::LatencyInfo& latency) {
+  render_widget_host_->ForwardGestureEventWithLatencyInfo(event, latency);
+}
+
 void RenderWidgetHostViewMac::TransformPointToLocalCoordSpace(
     const gfx::Point& point,
     cc::SurfaceId original_surface,