Merge pull request #1693 from benbro/master

Use a reusable style sheet instead of creating a new tag for each rule.

src/fonts.js

@@ -3104,9 +3104,13 @@ var Font = (function FontClosure() {
                  window.btoa(data) + ');');
       var rule = "@font-face { font-family:'" + fontName + "';src:" + url + '}';
 
-      var styleElement = document.createElement('style');
+      var styleElement = document.getElementById('PDFJS_FONT_STYLE_TAG');
+      if (!styleElement) {
+          styleElement = document.createElement('style');
+          styleElement.id = 'PDFJS_FONT_STYLE_TAG';
           document.documentElement.getElementsByTagName('head')[0].appendChild(
             styleElement);
+      }
 
       var styleSheet = styleElement.sheet;
       styleSheet.insertRule(rule, styleSheet.cssRules.length);