DevTools: add test to verify simple selector behavior.

Source/devtools/front_end/elements/StylesSidebarPane.js

Index: Source/devtools/front_end/elements/StylesSidebarPane.js
diff --git a/Source/devtools/front_end/elements/StylesSidebarPane.js b/Source/devtools/front_end/elements/StylesSidebarPane.js
index 18f9506179b6c129e4e73883d8f8c41295c50b73..ec27d244ac72f7d5e5ecc8d4cd2ca21923cb4f1e 100644
--- a/Source/devtools/front_end/elements/StylesSidebarPane.js
+++ b/Source/devtools/front_end/elements/StylesSidebarPane.js
@@ -1874,7 +1874,7 @@ WebInspector.BlankStylePropertiesSection.prototype = {
         {
             var doesSelectorAffectSelectedNode = newRule.matchingSelectors.length > 0;
             var styleRule = { section: this, style: newRule.style, selectorText: newRule.selectorText, sourceURL: newRule.resourceURL(), rule: newRule };
-            this.makeNormal(styleRule);
+            this._makeNormal(styleRule);
 
             if (!doesSelectorAffectSelectedNode) {
                 this.noAffect = true;
@@ -1924,7 +1924,7 @@ WebInspector.BlankStylePropertiesSection.prototype = {
         this._parentPane.removeSection(this);
     },
 
-    makeNormal: function(styleRule)
+    _makeNormal: function(styleRule)
     {
         this.element.classList.remove("blank-section");
         this.styleRule = styleRule;