ClassesPaneWidget - Add ability to quickly preview autocompleted CSS classes.

third_party/WebKit/Source/devtools/front_end/sdk/DOMModel.js

Index: third_party/WebKit/Source/devtools/front_end/sdk/DOMModel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/DOMModel.js b/third_party/WebKit/Source/devtools/front_end/sdk/DOMModel.js
index 6bc82d010d84d0585b0595f006113f1d0655908b..47b664b9d3ed943b92685f3662b2206c5a9e0350 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/DOMModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/DOMModel.js
@@ -413,6 +413,15 @@ SDK.DOMNode = class {
   }
 
   /**
+  * @param {string} name
+  * @param {string} value
+  * @return {!Promise<?Protocol.Error>}
+  */
+  setAttributeValuePromise(name, value) {
+    return new Promise(fulfill => this.setAttributeValue(name, value, fulfill));
+  }
+
+  /**
    * @return {!Array<!SDK.DOMNode.Attribute>}
    */
   attributes() {