Support merged Dart-JS callstacks

Source/core/inspector/InjectedScriptExterns.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 117 matching lines @@
     /** @type {number} */
     this.sourceID;
     /** @type {number} */
     this.line;
     /** @type {number} */
     this.column;
     /** @type {*} */
     this.thisObject;
     /** @type {string} */
     this.stepInPositions;
+    /** @type {number} */
+    this.framePointerHigh;
+    /** @type {number} */
+    this.framePointerLow;
 }
 
 /**
  * @param {number} index
  */
 JavaScriptCallFrame.prototype.scopeType = function(index) { }
 
 JavaScriptCallFrame.prototype.restart = function() { }
 
 /**
@@ skipping 35 matching lines @@
 // FIXME: Remove once ES6 is supported natively by JS compiler.
 
 /** @typedef {string} */
 var symbol;
 
 /**
  * @param {string} description
  * @return {symbol}
  */
 function Symbol(description) {}