fix for bug 205895 - make nsIMIMEInfo.getFileExtensions use a string enumerator, to avoid excess allocation at startup

r=bz, sr=darin

suite/common/contentAreaUtils.js

@@ -619,18 +619,19 @@ function appendFiltersForContentType(aFilePicker, aContentType, aSaveMode)
 
     var mimeInfo = getMIMEInfoForType(aContentType);
     if (mimeInfo) {
-      var extCount = { };
-      var extList = { };
-      mimeInfo.GetFileExtensions(extCount, extList);
+      
+      var extEnumerator = mimeInfo.getFileExtensions();
 
       var extString = "";
-      for (var i = 0; i < extCount.value; ++i) {
-        if (i > 0) 
-          extString += "; "; // If adding more than one extension, separate by semi-colon
-        extString += "*." + extList.value[i];
+      while (extEnumerator.hasMore()) {
+        var extension = extEnumerator.getNext();
+        if (extString)
+          extString += "; ";    // If adding more than one extension,
+                                // separate by semi-colon
+        extString += "*." + extension;
       }
-      
-      if (extCount.value > 0) {
+        
+      if (extString) {
         aFilePicker.appendFilter(mimeInfo.Description, extString);
       }
     }