Fix nit and comment

src/core/ReactNativeComponent.js

@@ -253,14 +253,12 @@ ReactNativeComponent.Mixin = {
         if (nextProp) {
           nextProp = nextProps.style = merge(nextProp);
         }
-        if (lastProp) {
-          for (styleName in lastProp) {
-            if (lastProp.hasOwnProperty(styleName) && !nextProp[styleName]) {
-              if (!styleUpdates) {
-                styleUpdates = {};
-              }
-              styleUpdates[styleName] = '';
+        for (styleName in lastProp) {
+          if (lastProp.hasOwnProperty(styleName) && !nextProp[styleName]) {
+            if (!styleUpdates) {
+              styleUpdates = {};
             }
+            styleUpdates[styleName] = '';
           }
         }
         for (styleName in nextProp) {

src/dom/DOMProperty.js

@@ -107,9 +107,8 @@ var DOMProperty = {
    * attribute). Most default values are '' or false, but not all. Worse yet,
    * some (in particular, `type`) vary depending on the type of element.
    *
-   * TODO: Is it worth caching the test elements? Caching the properties
-   * ourselves (as opposed to accessing from a cached test element every time)
-   * looks probably worth it: http://jsperf.com/object-vs-element
+   * TODO: Is it better to grab all the possible properties when creating an
+   * element to avoid having to create the same element twice?
    */
   getDefaultValueForProperty: function(nodeName, prop) {
     var nodeDefaults = defaultValueCache[nodeName];