b=495392 protect against bogus GdkAtoms from gtk_selection_data_get_targets() r=karlt

widget/src/gtk2/nsClipboard.cpp

@@ -452,6 +452,9 @@ nsClipboard::HasDataMatchingFlavors(const char** aFlavorList, PRUint32 aLength,
 
         for (PRInt32 j = 0; j < n_targets; j++) {
             gchar *atom_name = gdk_atom_name(targets[j]);
+            if (!atom_name)
+                continue;
+
             if (!strcmp(atom_name, aFlavorList[i]))
                 *_retval = PR_TRUE;
 

widget/src/gtk2/nsDragService.cpp

@@ -981,7 +981,7 @@ nsDragService::IsTargetContextList(void)
         GdkAtom atom = GDK_POINTER_TO_ATOM(tmp->data);
         gchar *name = NULL;
         name = gdk_atom_name(atom);
-        if (strcmp(name, gMimeListType) == 0)
+        if (name && strcmp(name, gMimeListType) == 0)
             retval = PR_TRUE;
         g_free(name);
         if (retval)