Add comment and fix typo

src/lib/style-properties.html

@@ -349,7 +349,12 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 
       // Strategy: x scope shim a selector e.g. to scope `.x-foo-42` (via classes):
       // non-host selector: .a.x-foo -> .x-foo-42 .a.x-foo
-      // host selector: x-foo.wide -> x-foo.x-foo-42.wide
+      // host selector: x-foo.wide -> .x-foo-42.wide
+      // note: we use only the scope class (.x-foo-42) and not the hostSelector
+      // (x-foo) to scope :host rules; this helps make property host rules
+      // have low specificity. They are overrideable by class selectors but,
+      // unfortunately, not by type selectors (e.g. overriding via 
+      // `.special` is ok, but not by `x-foo`).
       _scopeSelector: function(rule, hostRx, hostSelector, viaAttr, scopeId) {
         rule.transformedSelector = rule.transformedSelector || rule.selector;
         var selector = rule.transformedSelector;

src/standard/x-styling.html

@@ -18,6 +18,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     var serializeValueToAttribute = Polymer.Base.serializeValueToAttribute;
 
     var propertyUtils = Polymer.StyleProperties;
+    var styleUtil = Polymer.StyleUtil;
     var styleTransformer = Polymer.StyleTransformer;
     var styleDefaults = Polymer.StyleDefaults;