[DevTools] Migrate usages of Target to RuntimeModel where makes sense

third_party/WebKit/Source/devtools/front_end/main/Main.js

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2007 Matt Lilek (pewtermoose@gmail.com).
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * 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
@@ skipping 470 matching lines @@
    */
   detached(reason) {
     Main._disconnectedScreenWithReasonWasShown = true;
     Main.RemoteDebuggingTerminatedScreen.show(reason);
   }
 
   /**
    * @override
    */
   targetCrashed() {
-    var debuggerModel = SDK.DebuggerModel.fromTarget(this._target);
+    var debuggerModel = this._target.model(SDK.DebuggerModel);
     if (debuggerModel)
       Main.TargetCrashedScreen.show(debuggerModel);
   }
 };
 
 /**
  * @implements {UI.ActionDelegate}
  * @unrestricted
  */
 Main.Main.ReloadActionDelegate = class {
@@ skipping 447 matching lines @@
    * @override
    * @return {?Element}
    */
   settingElement() {
     return UI.SettingsUI.createSettingCheckbox(
         Common.UIString('Show rulers'), Common.moduleSetting('showMetricsRulers'));
   }
 };
 
 new Main.Main();