Bug 537120 part 2: be more conservative as far as application of converters goes. r=jst

uriloader/base/nsURILoader.cpp

@@ -437,7 +437,8 @@ nsresult nsDocumentOpenInfo::DispatchContent(nsIRequest *request, nsISupports *
       return NS_OK;
     }
 
-    // If we aren't allowed to try other listeners, we're done here.
+    // If we aren't allowed to try other listeners, just skip through to
+    // trying to convert the data.
     if (!(mFlags & nsIURILoader::DONT_RETARGET)) {
 
       //
@@ -516,26 +517,16 @@ nsresult nsDocumentOpenInfo::DispatchContent(nsIRequest *request, nsISupports *
           return rv;
         }
       }
+    } else {
+      LOG(("  DONT_RETARGET flag set, so skipped over random other content "
+           "listeners and content handlers"));
     }
-  } else if (mFlags & nsIURILoader::DONT_RETARGET) {
-    // External handling was forced, but we must not retarget
-    // -> abort
-    LOG(("  External handling forced, but not allowed to retarget -> aborting"));
-    return NS_ERROR_WONT_HANDLE_CONTENT;
-  }
-
-  NS_ASSERTION(!m_targetStreamListener,
-               "If we found a listener, why are we not using it?");
 
     //
     // Fifth step:  If no listener prefers this type, see if any stream
     //              converters exist to transform this content type into
     //              some other.
     //
-
-  // We always want to do this, since even content being forced to
-  // be handled externally may need decoding (eg via the unknown
-  // content decoder).
     // Don't do this if the server sent us a MIME type of "*/*" because they saw
     // it in our Accept header and got confused.
     // XXXbz have to be careful here; may end up in some sort of bizarre infinite
@@ -551,9 +542,14 @@ nsresult nsDocumentOpenInfo::DispatchContent(nsIRequest *request, nsISupports *
         return NS_OK;
       }
     }
+  }
+
+  NS_ASSERTION(!m_targetStreamListener,
+               "If we found a listener, why are we not using it?");
   
   if (mFlags & nsIURILoader::DONT_RETARGET) {
-    LOG(("  Listener not interested and no stream converter exists, and retargeting disallowed -> aborting"));
+    LOG(("  External handling forced or (listener not interested and no "
+         "stream converter exists), and retargeting disallowed -> aborting"));
     return NS_ERROR_WONT_HANDLE_CONTENT;
   }