[DevTools] Add "never show" link to emulation warning.

Source/devtools/front_end/sdk/OverridesSupport.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 456 matching lines @@
         this.settings.overrideCSSMedia.addChangeListener(this._cssMediaChanged, this);
         this.settings.emulatedCSSMedia.addChangeListener(this._cssMediaChanged, this);
 
         this.settings._emulationEnabled.addChangeListener(this._networkConditionsChanged, this);
         this.settings.networkConditions.addChangeListener(this._networkConditionsChanged, this);
 
         this.settings._emulationEnabled.addChangeListener(this._showRulersChanged, this);
         WebInspector.settings.showMetricsRulers.addChangeListener(this._showRulersChanged, this);
         this._showRulersChanged();
 
-        WebInspector.settings.disableOverridesWarning.addChangeListener(this._dispatchWarningChanged, this);
-
         if (!this.emulationEnabled())
             return;
 
         if (this.settings.overrideDeviceOrientation.get())
             this._deviceOrientationChanged();
 
         if (this.settings.overrideGeolocation.get())
             this._geolocationPositionChanged();
 
         if (this.settings.emulateTouch.get())
@@ skipping 265 matching lines @@
     {
         this._userAgentWarningMessage = warningMessage;
         this._dispatchWarningChanged();
     },
 
     /**
      * @return {string}
      */
     warningMessage: function()
     {
-        return WebInspector.settings.disableOverridesWarning.get() ? "" : (this._deviceMetricsWarningMessage || this._userAgentWarningMessage || "");
+        return this._deviceMetricsWarningMessage || this._userAgentWarningMessage || "";
     },
 
     clearWarningMessage: function()
     {
         this._deviceMetricsWarningMessage = "";
         this._userAgentWarningMessage = "";
         this._dispatchWarningChanged();
     },
 
     /**
@@ skipping 43 matching lines @@
     },
 
     __proto__: WebInspector.Object.prototype
 }
 
 
 /**
  * @type {!WebInspector.OverridesSupport}
  */
 WebInspector.overridesSupport;