Make pause-on-exceptions toggle/tri-state button.

Source/devtools/front_end/DebuggerModel.js

 /*
  * Copyright (C) 2010 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 31 matching lines @@
     this._scripts = {};
     /** @type {!Object.<!string, !Array.<!WebInspector.Script>>} */
     this._scriptsBySourceURL = {};
 
     this._canSetScriptSource = false;
     this._breakpointsActive = true;
 
     WebInspector.settings.pauseOnExceptionStateString = WebInspector.settings.createSetting("pauseOnExceptionStateString", WebInspector.DebuggerModel.PauseOnExceptionsState.DontPauseOnExceptions);
     WebInspector.settings.pauseOnExceptionStateString.addChangeListener(this._pauseOnExceptionStateChanged, this);
 
+    WebInspector.settings.lastPauseOnExceptionState = WebInspector.settings.createSetting("lastPauseOnExceptionState", WebInspector.DebuggerModel.PauseOnExceptionsState.PauseOnUncaughtExceptions);
+
     WebInspector.settings.enableAsyncStackTraces.addChangeListener(this._asyncStackTracesStateChanged, this);
 
     this.enableDebugger();
 
     WebInspector.DebuggerModel.applySkipStackFrameSettings();
 }
 
-// Keep these in sync with WebCore::ScriptDebugServer
+/**
+ * Keep these in sync with WebCore::ScriptDebugServer
+ *
+ * @enum {string}
+ */
 WebInspector.DebuggerModel.PauseOnExceptionsState = {
     DontPauseOnExceptions : "none",
     PauseOnAllExceptions : "all",
     PauseOnUncaughtExceptions: "uncaught"
 };
 
 /**
  * @constructor
  * @implements {WebInspector.RawLocation}
  * @param {string} scriptId
@@ skipping 1001 matching lines @@
             this.callFrames[i].dispose();
         if (this.asyncStackTrace)
             this.asyncStackTrace.dispose();
     }
 }
 
 /**
  * @type {!WebInspector.DebuggerModel}
  */
 WebInspector.debuggerModel;