Babel-ified code works in Chrome but not Chromium (37)

babel-issue.js

    _getItemIdStrs() {
        const result = []
        const itemIdStrings = Object.keys(this.state)
        for (const itemIdStr of itemIdStrings) {
            if (itemIdStr !== 'groups') {
                result.push(itemIdStr)
            }
        }
        return result
    }
    
/* Gets transpiled to: */
    
    {
	        key: '_getItemIdStrs',
	        value: function _getItemIdStrs() {
	            var result = [];
	            var _iteratorNormalCompletion = true;
	            var _didIteratorError = false;
	            var _iteratorError = undefined;

	            try {
	                for (var _iterator = Object.keys(this.state)[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
	                    var itemIdStr = _step.value;

	                    if (itemIdStr !== 'groups') {
	                        result.push(itemIdStr);
	                    }
	                }
	            } catch (err) {
	                _didIteratorError = true;
	                _iteratorError = err;
	            } finally {
	                try {
	                    if (!_iteratorNormalCompletion && _iterator['return']) {
	                        _iterator['return']();
	                    }
	                } finally {
	                    if (_didIteratorError) {
	                        throw _iteratorError;
	                    }
	                }
	            }

	            return result;
	        }

/* Gets 'undefined' is not a function at line 23 at Object.keys(this.state)[Symbol.iterator]() (specifically the Symbol.iterator key function call)