Replace boolean indications of strict mode by an enum value.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 6c1d2698b523a0c2cb7c26c69247c9ac9d99136e..2e063c9dafe1f51283f4fc2437e995be3a2cd89d 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4840,7 +4840,11 @@ class SharedFunctionInfo: public HeapObject {
   DECL_BOOLEAN_ACCESSORS(optimization_disabled)
 
   // Indicates whether the function is a strict mode function.
-  DECL_BOOLEAN_ACCESSORS(strict_mode)
+  inline bool strict_mode();
+
+  // Indicates the mode of the function.
+  inline StrictModeFlag strict_mode_flag();
+  inline void set_strict_mode_flag(StrictModeFlag strict_mode_flag);
 
   // False if the function definitely does not allocate an arguments object.
   DECL_BOOLEAN_ACCESSORS(uses_arguments)