We missed this because Flow wasn't being run properly on Travis but now that it is, it's clear that #7716 introduced a bunch of new Flow failures. Most of these shouldn't be too bad and I like to say "you break it you buy it" so this one is for you @Aweary :)

There were a couple other pre-existing Flow issues that @vjeux is going to fix, so mostly this should just be the TestRenderer issues.

ret = escapeTextContentForBrowser(contentToUse);
        if (__DEV__) {
          setAndValidateContentChildDev.call(this, contentToUse);
        }
      } else if (childrenToUse != null) {
        var mountImages = this.mountChildren(
          childrenToUse,
          transaction,
          context
        );
        ret = mountImages.join('');
      }
    }
    if (newlineEatingTags[this._tag] && ret.charAt(0) === '\n') {
      
      
      
      
      
      
      
      
      
      
      return '\n' + ret;
    } else {
      return ret;
    }
  },
  _createInitialChildren: function(transaction, props, context, lazyTree) {