DevTools: migrate from ui-setting to settings extension point.

Source/devtools/front_end/Runtime.js

Index: Source/devtools/front_end/Runtime.js
diff --git a/Source/devtools/front_end/Runtime.js b/Source/devtools/front_end/Runtime.js
index b2fcc190e7d1495ff01bf8e51dbaade32a72988d..cf3c444be03eea2967b52fea45d9748f0db57043 100644
--- a/Source/devtools/front_end/Runtime.js
+++ b/Source/devtools/front_end/Runtime.js
@@ -861,6 +861,15 @@ Runtime.Extension.prototype = {
                 return Promise.reject("Could not instantiate: " + className);
             return result;
         }
+    },
+
+    /**
+     * @param {string} platform
+     * @return {string}
+     */
+    title: function(platform)
+    {
+        return this._descriptor["title-" + platform] || this._descriptor["title"];
     }
 }