Add support for context-aware cloning functions

Summary:
@public

Context-aware cloning functions are an internal Yoga feature that will be used for Yoga’s JNI code.

It will be possible to specify a context when calculating layout, which will be passed on to cloning functions. This will be a private feature.

Reviewed By: SidharthGuglani

Differential Revision: D14149470

fbshipit-source-id: 1d11106e65f9d872d10f191763da001f8d158a61

yoga/YGNode.cpp

@@ -385,8 +385,8 @@ void YGNode::clearChildren() {
 
 // Other Methods
 
-void YGNode::cloneChildrenIfNeeded() {
-  iterChildrenAfterCloningIfNeeded([](YGNodeRef) {});
+void YGNode::cloneChildrenIfNeeded(void* cloneContext) {
+  iterChildrenAfterCloningIfNeeded([](YGNodeRef, void*) {}, cloneContext);
 }
 
 void YGNode::markDirtyAndPropogate() {