Implement JSON serialization for Gradient and GradientColor.

src/color/Color.js

@@ -320,8 +320,8 @@ var Color = this.Color = Base.extend(new function() {
 			 * @ignore
 			 */
 			extend: function(src) {
-				if (src._type) {
-					var comps = components[src._type];
+				var comps = components[src._type];
+				if (comps) {
 					// Automatically produce the _components field, adding alpha
 					src._components = comps.concat(['alpha']);
 					Base.each(comps, function(name) {

src/color/Gradient.js

@@ -33,6 +33,11 @@ var Gradient = this.Gradient = Base.extend(/** @lends Gradient# */{
 		this.type = type || 'linear';
 	},
 
+	_serialize: function(dictionary) {
+		return dictionary.get(this) || dictionary.set(this, Base.serialize(
+				[this._type, this._stops, this.type], true, dictionary));
+	},
+
 	/**
 	 * Called by various setters whenever a gradient value changes
 	 */

src/color/GradientColor.js

@@ -16,6 +16,7 @@
  * @class The GradientColor object.
  */
 var GradientColor = this.GradientColor = Color.extend(/** @lends GradientColor# */{
+	_type: 'gradientcolor',
 
 	/**
 	 * Creates a gradient color object.
@@ -97,6 +98,13 @@ var GradientColor = this.GradientColor = Color.extend(/** @lends GradientColor#
 				this._hilite);
 	},
 
+	_serialize: function(dictionary) {
+		var values = [ this.gradient, this._origin, this._destination ];
+		if (this._hilite)
+			values.push(this._hilite);
+		return Base.serialize(values, true, dictionary);
+	},
+
 	/**
 	 * The origin point of the gradient.
 	 *

src/color/GradientStop.js

@@ -53,6 +53,10 @@ var GradientStop = this.GradientStop = Base.extend(/** @lends GradientStop# */{
 		return new GradientStop(this._color.clone(), this._rampPoint);
 	},
 
+	_serialize: function(dictionary) {
+		return Base.serialize([this._color, this._rampPoint], false, dictionary);
+	},
+
 	/**
 	 * Called by various setters whenever a value changes
 	 */