Add Mojo API for Blink hit testing

services/viz/public/interfaces/hit_test/target_frame_for_input_delegate.mojom

Index: services/viz/public/interfaces/hit_test/target_frame_for_input_delegate.mojom
diff --git a/services/viz/public/interfaces/hit_test/target_frame_for_input_delegate.mojom b/services/viz/public/interfaces/hit_test/target_frame_for_input_delegate.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..61b879092718cf751e69b440704cfaf98b35d1fd
--- /dev/null
+++ b/services/viz/public/interfaces/hit_test/target_frame_for_input_delegate.mojom
@@ -0,0 +1,11 @@
+module viz.mojom;
+
+import "ui/gfx/geometry/mojo/geometry.mojom";
+  
+// TODO(nzolghadr): This interface should be relocated to servcices/ui/public
+// when all Chrome implementation use the services/ui windows server.
+
+// Returns the hit-tested remote frame id for the given coordinates.
+interface TargetFrameForInputDelegate {
+  HitTestFrameAt(gfx.mojom.Point point) => (int32 frame_id);
+};