mshtml: Introduce ES6 JavaScript mode and use it in IE11 compat mode.

dlls/jscript/jscript.h

@@ -42,9 +42,10 @@
 #define SCRIPTLANGUAGEVERSION_HTML 0x400
 
 /*
- * This is Wine jscript extension for ES5 compatible mode. Allowed only in HTML mode.
+ * This is Wine jscript extension for ES5 and ES6 compatible mode. Allowed only in HTML mode.
  */
 #define SCRIPTLANGUAGEVERSION_ES5  0x102
+#define SCRIPTLANGUAGEVERSION_ES6  0x103
 
 typedef struct _jsval_t jsval_t;
 typedef struct _jsstr_t jsstr_t;

dlls/mshtml/script.c

@@ -66,6 +66,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(mshtml);
 /* See jscript.h in jscript.dll. */
 #define SCRIPTLANGUAGEVERSION_HTML 0x400
 #define SCRIPTLANGUAGEVERSION_ES5  0x102
+#define SCRIPTLANGUAGEVERSION_ES6  0x103
 
 struct ScriptHost {
     IActiveScriptSite              IActiveScriptSite_iface;
@@ -154,7 +155,9 @@ static BOOL init_script_engine(ScriptHost *script_host)
     compat_mode = lock_document_mode(script_host->window->doc);
     script_mode = compat_mode < COMPAT_MODE_IE8 ? SCRIPTLANGUAGEVERSION_5_7 : SCRIPTLANGUAGEVERSION_5_8;
     if(IsEqualGUID(&script_host->guid, &CLSID_JScript)) {
-        if(compat_mode >= COMPAT_MODE_IE9)
+        if(compat_mode >= COMPAT_MODE_IE11)
+            script_mode = SCRIPTLANGUAGEVERSION_ES6;
+        else if(compat_mode >= COMPAT_MODE_IE9)
             script_mode = SCRIPTLANGUAGEVERSION_ES5;
         script_mode |= SCRIPTLANGUAGEVERSION_HTML;
     }