Revert of cc: Fix size_t to int truncations in layers/ output/ playback/ quads/

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index a1234c1d404359bd3cf9678269176777e8d28cab..84e9c0f8ba69c65fa70ce676ed5cc1f6e61e0ae7 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -670,6 +670,9 @@
   // This should only be called during BeginMainFrame since it does not
   // trigger a Commit.
   void SetHasRenderSurface(bool has_render_surface);
+
+  // Returns the index of the child or -1 if not found.
+  int IndexOfChild(const Layer* reference);
 
   // This should only be called from RemoveFromParent().
   void RemoveChildOrDependent(Layer* child);