Adds an interface to SurfaceHittestDelegate in order to override

cc/surfaces/surface_hittest.cc

Index: cc/surfaces/surface_hittest.cc
diff --git a/cc/surfaces/surface_hittest.cc b/cc/surfaces/surface_hittest.cc
index 1f443d64814913f0d8cef5a2ce08e9acdab0482d..6db66e244142ef081f08630dcc7f35ec7df56642 100644
--- a/cc/surfaces/surface_hittest.cc
+++ b/cc/surfaces/surface_hittest.cc
@@ -104,7 +104,10 @@ bool SurfaceHittest::GetTargetSurfaceAtPointInternal(
       gfx::Transform transform_to_child_space;
       if (GetTargetSurfaceAtPointInternal(
               surface_quad->surface_id, RenderPassId(), point_in_quad_space,
-              referenced_passes, out_surface_id, &transform_to_child_space)) {
+              referenced_passes, out_surface_id, &transform_to_child_space) ||
+          (delegate_ &&
+           delegate_->AcceptHitTarget(surface_quad, point_in_quad_space))) {
+        *out_surface_id = surface_quad->surface_id;
         *out_transform = transform_to_child_space * target_to_quad_transform *
                          transform_from_root_target;
         return true;