Instant Extended: Suppress mouse events for bottom web content

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 6bad9f931d7ce54b731206340e7d0d1f1f523e44..9351ddc7921452402e341ac89b5cd1bca1ec653e 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -1733,6 +1733,12 @@ gfx::Rect RenderWidgetHostViewMac::GetScaledOpenGLPixelRect(
       // The cursor is over a nonWebContentView - ignore this mouse event.
       return YES;
     }
+    if ([view isKindOfClass:[self class]] && ![view isEqual:self]) {
+      // The cursor is over an overlapping render widget. This check is done by
+      // both views so the one that's returned by -hitTest: will end up
+      // processing the event.
+      return YES;
+    }
     view = [view superview];
   }
   return NO;