Update constructors view when switching perspectives

Source/devtools/front_end/HeapSnapshotDataGrids.js

 /*
  * 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:
  *
  *     * 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 751 matching lines @@
                 var parent = constructorNodes[i];
                 if (parent._name === className) {
                     parent.revealNodeBySnapshotObjectId(parseInt(id, 10), callback);
                     return;
                 }
             }
         }
         this.snapshot.nodeClassName(parseInt(id, 10), didGetClassName.bind(this));
     },
 
+    clear: function()
+    {
+        this._nextRequestedFilter = null;
+        this._lastFilter = null;
+        this.removeTopLevelNodes();
+    },
+
     setDataSource: function(snapshot)
     {
         this.snapshot = snapshot;
         if (this._profileIndex === -1)
             this._populateChildren();
 
         if (this._objectIdToSelect) {
             this.highlightObjectByHeapSnapshotId(this._objectIdToSelect, function(found) {});
             this._objectIdToSelect = null;
         }
@@ skipping 422 matching lines @@
      * @return {number}
      */
     allocationNodeId: function()
     {
         return this.data.id;
     },
 
     __proto__: WebInspector.DataGridNode.prototype
 }