escape XML in SVG strings

src/text.class.js

@@ -328,7 +328,7 @@
               toFixed(lineTopOffset + (i === 0 ? this._shadowOffsets[j][1] : 0), 2),
               '" ',
               this._getFillAttributes(this._shadows[j].color), '>',
-              textLines[i],
+              fabric.util.string.escapeXml(textLines[i]),
             '</tspan>');
             lineTopOffsetMultiplier = 1;
           } else {
@@ -355,7 +355,7 @@
             toFixed(lineTopOffset * lineTopOffsetMultiplier, 2) , '" ',
             // doing this on <tspan> elements since setting opacity on containing <text> one doesn't work in Illustrator
             this._getFillAttributes(this.fill), '>',
-            textLines[i],
+            fabric.util.string.escapeXml(textLines[i]),
             '</tspan>'
           );
           lineTopOffsetMultiplier = 1;

src/util/lang_string.js

@@ -1,3 +1,5 @@
+(function() {
+
 if (!String.prototype.trim) {
   /**
    * Trims a string (removing whitespace from the beginning and the end)
@@ -34,8 +36,18 @@ function capitalize(string) {
   return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
 }
 
+function escapeXml(string) {
+  return string.replace('&', '&')
+     .replace('"', '"')
+     .replace("'", ''')
+     .replace("<", '&lt;')
+     .replace(">", '&gt;');
+}
+
 /** @namespace */
 fabric.util.string = {
   camelize: camelize,
-  capitalize: capitalize
-};
+  capitalize: capitalize,
+  escapeXml: escapeXml
+};
+}());