DevTools: Migrate General tab settings to extensions

Source/devtools/front_end/utilities.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 1373 matching lines @@
     {
         this._map = {};
         this._size = 0;
         delete this._hasProtoKey;
         delete this._protoValue;
     }
 }
 
 /**
  * @constructor
+ * @extends {StringMap.<Set.<!T>>}
+ * @template T
+ */
+var StringMultimap = function()
+{
+    StringMap.call(this);
+}
+
+StringMultimap.prototype = {
+    /**
+     * @param {string} key
+     * @param {T} value
+     */
+    put: function(key, value)
+    {
+        if (key === "__proto__") {
+            if (!this._hasProtoKey) {
+                ++this._size;
+                this._hasProtoKey = true;
+                /** @type {!Set.<T>} */
+                this._protoValue = new Set();
+            }
+            this._protoValue.add(value);
+            return;
+        }
+        if (!Object.prototype.hasOwnProperty.call(this._map, key)) {
+            ++this._size;
+            this._map[key] = new Set();
+        }
+        this._map[key].add(value);
+    },
+
+    __proto__: StringMap.prototype
+}
+
+/**
+ * @constructor
  */
 var StringSet = function()
 {
     /** @type {!StringMap.<boolean>} */
     this._map = new StringMap();
 }
 
 StringSet.prototype = {
     /**
      * @param {string} value
@@ skipping 156 matching lines @@
             this._outgoingCallback();
     }
 }
 
 /**
  * @param {*} value
  */
 function suppressUnused(value)
 {
 }