Fixing bug 431280. Sniff the URI file extension for a mimetype to use if the one given in an embed elements type attribute isn't a supported type. r+sr=bzbarsky@mit.edu, a=dsicore@mozilla.com

content/base/src/nsObjectLoadingContent.cpp

@@ -1075,11 +1075,8 @@ nsObjectLoadingContent::LoadObject(nsIURI* aURI,
 
   nsCAutoString overrideType;
   if ((caps & eOverrideServerType) &&
-      (!aTypeHint.IsEmpty() ||
+      ((!aTypeHint.IsEmpty() && IsSupportedPlugin(aTypeHint)) ||
        (aURI && IsPluginEnabledByExtension(aURI, overrideType)))) {
-    NS_ASSERTION(aTypeHint.IsEmpty() ^ overrideType.IsEmpty(),
-                 "Exactly one of aTypeHint and overrideType should be empty!");
-
     ObjectType newType;
     if (overrideType.IsEmpty()) {
       newType = GetTypeOfContent(aTypeHint);