Introduce extended mode.

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index f5edd623e78b9f8c59da3e3cc78ac81c0ea7c807..ef197d30d8e1f5055d69e235f8e2ea19aa705e24 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -1224,7 +1224,7 @@ class LStoreGlobalGeneric: public LTemplateInstruction<0, 2, 0> {
   LOperand* global_object() { return InputAt(0); }
   Handle<Object> name() const { return hydrogen()->name(); }
   LOperand* value() { return InputAt(1); }
-  bool strict_mode() { return hydrogen()->strict_mode(); }
+  StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };
 
 
@@ -1573,7 +1573,6 @@ class LStoreNamedGeneric: public LTemplateInstruction<0, 2, 0> {
   LOperand* value() { return inputs_[1]; }
   Handle<Object> name() const { return hydrogen()->name(); }
   StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
-  bool strict_mode() { return strict_mode_flag() == kStrictMode; }
 };
 
 
@@ -1658,7 +1657,7 @@ class LStoreKeyedGeneric: public LTemplateInstruction<0, 3, 0> {
   LOperand* object() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
   LOperand* value() { return inputs_[2]; }
-  bool strict_mode() { return hydrogen()->strict_mode(); }
+  StrictModeFlag strict_mode_flag() { return hydrogen()->strict_mode_flag(); }
 };