DevTools: use target-based model accessors only.

Source/devtools/front_end/sdk/RemoteObject.js

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 264 matching lines @@
     this._type = type;
     this._subtype = subtype;
     if (objectId) {
         // handle
         this._objectId = objectId;
         this._description = description;
         this._hasChildren = (type !== "symbol");
         this._preview = preview;
     } else {
         // Primitive or null object.
-        console.assert(type !== "object" || value === null);
         this._description = description || (value + "");
         this._hasChildren = false;
         // Handle special numbers: NaN, Infinity, -Infinity, -0.
         if (type === "number" && typeof value !== "number")
             this.value = Number(value);
         else
             this.value = value;
     }
     this._customPreview = customPreview || null;
 }
@@ skipping 897 matching lines @@
     {
         if (!this._cachedDescription) {
             var children = this._children();
             this._cachedDescription = "{" + this._formatValue(children[0].value) + " => " + this._formatValue(children[1].value) + "}";
         }
         return this._cachedDescription;
     },
 
     __proto__: WebInspector.LocalJSONObject.prototype
 }