Introduce LanguageMode, drop StrictMode.

src/ic/x64/ic-compiler-x64.cc

Index: src/ic/x64/ic-compiler-x64.cc
diff --git a/src/ic/x64/ic-compiler-x64.cc b/src/ic/x64/ic-compiler-x64.cc
index 5be9c465cc5e13283d9e94a73c5aa1aeba61e98e..eeae4d51e7976a82b20bf92933bc70dc62e0137d 100644
--- a/src/ic/x64/ic-compiler-x64.cc
+++ b/src/ic/x64/ic-compiler-x64.cc
@@ -15,8 +15,8 @@ namespace internal {
 #define __ ACCESS_MASM(masm)
 
 
-void PropertyICCompiler::GenerateRuntimeSetProperty(MacroAssembler* masm,
-                                                    StrictMode strict_mode) {
+void PropertyICCompiler::GenerateRuntimeSetProperty(
+    MacroAssembler* masm, LanguageMode language_mode) {
   // Return address is on the stack.
   DCHECK(!rbx.is(StoreDescriptor::ReceiverRegister()) &&
          !rbx.is(StoreDescriptor::NameRegister()) &&
@@ -26,7 +26,7 @@ void PropertyICCompiler::GenerateRuntimeSetProperty(MacroAssembler* masm,
   __ Push(StoreDescriptor::ReceiverRegister());
   __ Push(StoreDescriptor::NameRegister());
   __ Push(StoreDescriptor::ValueRegister());
-  __ Push(Smi::FromInt(strict_mode));
+  __ Push(Smi::FromInt(language_mode));
   __ PushReturnAddressFrom(rbx);
 
   // Do tail-call to runtime routine.