Merge pull request #594 from notmasteryet/bypasstype3

Properly bypass Type3 fonts (ref #577)

pdf.js

@@ -4563,6 +4563,8 @@ var PartialEvaluator = (function partialEvaluator() {
             break;
           default:
             warn('Unknown type of font: ' + type);
+            baseEncoding = [];
+            break;
         }
       }
 
@@ -4749,9 +4751,10 @@ var PartialEvaluator = (function partialEvaluator() {
       // This case is here for compatibility.
       var descriptor = xref.fetchIfRef(dict.get('FontDescriptor'));
       if (!descriptor) {
-        var baseFontName = dict.get('BaseFont');
-        if (!isName(baseFontName))
-          return null;
+        // Note for Type3 fonts: it has no no base font, feeding default
+        // font name and trying to get font metrics as the same way as for
+        // a font without descriptor.
+        var baseFontName = dict.get('BaseFont') || new Name('sans-serif');
 
         // Using base font name as a font name.
         baseFontName = baseFontName.name.replace(/,/g, '_');