DevTools: spectrum should switch to rgba upon adding alpha on drag.

Source/devtools/front_end/elements/Spectrum.js

 /*
  * Copyright (C) 2011 Brian Grinstead 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
@@ skipping 141 matching lines @@
     /**
      * @param {!Event} event
      * @this {WebInspector.Spectrum}
      */
     function positionAlpha(event)
     {
         var newAlpha = Math.round((event.x - this._hueAlphaLeft) / this._hueAlphaWidth * 100) / 100;
         var hsva = this._hsv.slice();
         hsva[3] = Number.constrain(newAlpha, 0, 1);
         var colorFormat = undefined;
-        if (this._color().hasAlpha() && (this._colorFormat === WebInspector.Color.Format.ShortHEX || this._colorFormat === WebInspector.Color.Format.HEX || this._colorFormat === WebInspector.Color.Format.Nickname))
+        if (hsva[3] !== 1 && (this._colorFormat === WebInspector.Color.Format.ShortHEX || this._colorFormat === WebInspector.Color.Format.HEX || this._colorFormat === WebInspector.Color.Format.Nickname))
             colorFormat = WebInspector.Color.Format.RGB;
         this._innerSetColor(hsva, "", colorFormat, WebInspector.Spectrum._ChangeSource.Other);
     }
 
     /**
      * @param {!Event} event
      * @this {WebInspector.Spectrum}
      */
     function positionColor(event)
     {
@@ skipping 721 matching lines @@
     "#8BC34A",
     "#CDDC39",
     "#FFEB3B",
     "#FFC107",
     "#FF9800",
     "#FF5722",
     "#795548",
     "#9E9E9E",
     "#607D8B"
 ]};