Fix a crash bug on user script installation

chrome/renderer/user_script_slave.cc

Index: chrome/renderer/user_script_slave.cc
diff --git a/chrome/renderer/user_script_slave.cc b/chrome/renderer/user_script_slave.cc
index 68dec433471cfaedb7ea8e87babf001dbc009167..7ddbd716921d888de6a77e4260660c35aa4c1b13 100644
--- a/chrome/renderer/user_script_slave.cc
+++ b/chrome/renderer/user_script_slave.cc
@@ -189,7 +189,7 @@ bool UserScriptSlave::InjectScripts(WebFrame* frame,
 
         // We add this dumb function wrapper for standalone user script to
         // emulate what Greasemonkey does.
-        if (script->is_standalone()) {
+        if (script->is_standalone() || script->emulate_greasemonkey()) {
           content.insert(0, kUserScriptHead);
           content += kUserScriptTail;
         }