DevTools: [Styles] Display color swatch for editable styles

Source/devtools/front_end/StylesSidebarPane.js

Index: Source/devtools/front_end/StylesSidebarPane.js
diff --git a/Source/devtools/front_end/StylesSidebarPane.js b/Source/devtools/front_end/StylesSidebarPane.js
index 0e6a43946146e2c2125b0e7bf569a3ec4b1d4818..1c2160e90436538a1338d86696a30d59f2ac0df0 100644
--- a/Source/devtools/front_end/StylesSidebarPane.js
+++ b/Source/devtools/front_end/StylesSidebarPane.js
@@ -1956,7 +1956,7 @@ WebInspector.StylePropertyTreeElementBase.prototype = {
         var spectrumHelper = this.editablePane() && this.editablePane()._spectrumHelper;
         var spectrum = spectrumHelper ? spectrumHelper.spectrum() : null;
 
-        var isEditable = !!(this._styleRule && this._styleRule.editable);
+        var isEditable = !!(this._styleRule && this._styleRule.editable !== false); // |editable| is true by default.
         var colorSwatch = new WebInspector.ColorSwatch(!isEditable);
         colorSwatch.setColorString(text);
         colorSwatch.element.addEventListener("click", swatchClick.bind(this), false);