dijit._Container.getIndexOfChild() code reduction

[Les]

This is lightly tested.

These two methods should be functionally equivalent, but the last one is simpler and shorter.

getIndexOfChild: function(/*Widget*/ child){
	// summary:
	//		Gets the index of the child in this container or -1 if not found
	var children = this.getChildren();
	for(var i=0, c; c=children[i]; i++){
		if(c == child){ 
			return i; // int
		}
	}
	return -1; // int
}

getIndexOfChild: function(/*Widget*/ child){
	// summary:
	//		Gets the index of the child in this container or -1 if not found
	return dojo.indexOf(this.getChildren(), child);
}

[bill]

That does seem shorter, although it strikes me as strange that both the old and new code is comparing _Widget objects rather than just comparing the widget id's.

[bill]

Anyway, I will make your suggested change, thanks!

[bill]

(In [20280]) dijit._Contained and dijit._Container code reduction from Les (CLA on file) and me.

Seems like there is still a lot of redundancy though between _Container (_getSiblingOfChild, _nextElement) and _Contained (_getSibling, _getPrevSibling, _getNextSibling). The only difference I see is that _Container._getSiblingOfChild() skips over non-Widget siblings; not sure if/why that code is needed. Also might make sense to just use dojo.query() for these methods.

Also updating API doc for return codes.

Fixes #9985, #9986 !strict.