Make "three snapshot technique" work on heap snapshots loaded from files

Source/devtools/front_end/CPUProfileView.js

 /*
  * Copyright (C) 2008 Apple 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 731 matching lines @@
         return new WebInspector.CPUProfileHeader(this, profile.title, profile.uid);
     },
 
     /**
      * @override
      * @param {!WebInspector.ProfileHeader} profile
      */
     removeProfile: function(profile)
     {
         WebInspector.ProfileType.prototype.removeProfile.call(this, profile);
-        if (!profile.isTemporary)
+        if (!profile.isTemporary && !profile.fromFile())
             ProfilerAgent.removeProfile(this.id, profile.uid);
     },
 
     /**
      * @override
      * @param {function(this:WebInspector.ProfileType, ?string, Array.<ProfilerAgent.ProfileHeader>)} populateCallback
      */
     _requestProfilesFromBackend: function(populateCallback)
     {
         ProfilerAgent.getProfileHeaders(populateCallback);
@@ skipping 149 matching lines @@
         function onOpen()
         {
             ProfilerAgent.getCPUProfile(this.uid, getCPUProfileCallback.bind(this));
         }
 
         this._fileName = this._fileName || "CPU-" + new Date().toISO8601Compact() + this._profileType.fileExtension();
         fileOutputStream.open(this._fileName, onOpen.bind(this));
     },
 
     /**
-     * @param {File} file
+     * @param {!File} file
      */
     loadFromFile: function(file)
     {
-        this.title = file.name;
         this.sidebarElement.subtitle = WebInspector.UIString("Loading\u2026");
         this.sidebarElement.wait = true;
 
         var fileReader = new WebInspector.ChunkedFileReader(file, 10000000, this);
         fileReader.start(this);
     },
 
     __proto__: WebInspector.ProfileHeader.prototype
 }