Introduce LanguageMode, drop StrictMode.

src/api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 3065 matching lines @@
 
 
 bool v8::Object::SetPrivate(v8::Handle<Private> key, v8::Handle<Value> value) {
   return ForceSet(v8::Handle<Value>(reinterpret_cast<Value*>(*key)),
                   value, DontEnum);
 }
 
 
 i::MaybeHandle<i::Object> DeleteObjectProperty(
     i::Isolate* isolate, i::Handle<i::JSReceiver> receiver,
-    i::Handle<i::Object> key, i::StrictMode strict_mode) {
+    i::Handle<i::Object> key, i::LanguageMode language_mode) {
   // Check if the given key is an array index.
   uint32_t index;
   if (key->ToArrayIndex(&index)) {
     // In Firefox/SpiderMonkey, Safari and Opera you can access the
     // characters of a string using [] notation.  In the case of a
     // String object we just need to redirect the deletion to the
     // underlying string if the index is in range.  Since the
     // underlying string does nothing with the deletion, we can ignore
     // such deletions.
     if (receiver->IsStringObjectWithCharacterAt(index)) {
       return isolate->factory()->true_value();
     }
 
-    return i::JSReceiver::DeleteElement(receiver, index, strict_mode);
+    return i::JSReceiver::DeleteElement(receiver, index, language_mode);
   }
 
   i::Handle<i::Name> name;
   if (key->IsName()) {
     name = i::Handle<i::Name>::cast(key);
   } else {
     // Call-back into JavaScript to convert the key to a string.
     i::Handle<i::Object> converted;
     if (!i::Execution::ToString(isolate, key).ToHandle(&converted)) {
       return i::MaybeHandle<i::Object>();
     }
     name = i::Handle<i::String>::cast(converted);
   }
 
   if (name->IsString()) {
     name = i::String::Flatten(i::Handle<i::String>::cast(name));
   }
-  return i::JSReceiver::DeleteProperty(receiver, name, strict_mode);
+  return i::JSReceiver::DeleteProperty(receiver, name, language_mode);
 }
 
 
 Local<Value> v8::Object::Get(v8::Handle<Value> key) {
   i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
   ON_BAILOUT(isolate, "v8::Object::Get()", return Local<v8::Value>());
   ENTER_V8(isolate);
   i::Handle<i::Object> self = Utils::OpenHandle(this);
   i::Handle<i::Object> key_obj = Utils::OpenHandle(*key);
   EXCEPTION_PREAMBLE(isolate);
@@ skipping 4506 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 } }  // namespace v8::internal