Add strong mode.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 1bf74bea4303b8c7db3e7511ba4731d654b12cf0..b5a53dca21ef47e2cdeac3fd3a0cea719c5d0f28 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -5805,19 +5805,21 @@ void SharedFunctionInfo::set_optimization_disabled(bool disable) {
 
 
 LanguageMode SharedFunctionInfo::language_mode() {
-  STATIC_ASSERT(LANGUAGE_END == 2);
-  return BooleanBit::get(compiler_hints(), kStrictModeFunction)
-      ? STRICT : SLOPPY;
+  STATIC_ASSERT(LANGUAGE_END == 3);
+  return construct_language_mode(
+      BooleanBit::get(compiler_hints(), kStrictModeFunction),
+      BooleanBit::get(compiler_hints(), kSaneModeFunction));
 }
 
 
 void SharedFunctionInfo::set_language_mode(LanguageMode language_mode) {
-  STATIC_ASSERT(LANGUAGE_END == 2);
+  STATIC_ASSERT(LANGUAGE_END == 3);
   // We only allow language mode transitions that set the same language mode
   // again or go up in the chain:
   DCHECK(is_sloppy(this->language_mode()) || is_strict(language_mode));
   int hints = compiler_hints();
   hints = BooleanBit::set(hints, kStrictModeFunction, is_strict(language_mode));
+  hints = BooleanBit::set(hints, kSaneModeFunction, is_sane(language_mode));
   set_compiler_hints(hints);
 }