Reland of "Remove ExternalArray, derived types, and element kinds"

src/lookup.cc

Index: src/lookup.cc
diff --git a/src/lookup.cc b/src/lookup.cc
index 7d9f79168b8ec8969d83c03ef12ec040a817b13f..75d460328daf13eba580f8db59ba47afd9780b0b 100644
--- a/src/lookup.cc
+++ b/src/lookup.cc
@@ -117,8 +117,7 @@ void LookupIterator::ReloadPropertyInformation() {
 void LookupIterator::ReloadHolderMap() {
   DCHECK_EQ(DATA, state_);
   DCHECK(IsElement());
-  DCHECK(JSObject::cast(*holder_)->HasExternalArrayElements() ||
-         JSObject::cast(*holder_)->HasFixedTypedArrayElements());
+  DCHECK(JSObject::cast(*holder_)->HasFixedTypedArrayElements());
   if (*holder_map_ != holder_->map()) {
     holder_map_ = handle(holder_->map(), isolate_);
   }
@@ -161,7 +160,6 @@ void LookupIterator::ReconfigureDataProperty(Handle<Object> value,
   DCHECK(HolderIsReceiverOrHiddenPrototype());
   Handle<JSObject> holder = GetHolder<JSObject>();
   if (IsElement()) {
-    DCHECK(!holder->HasExternalArrayElements());
     DCHECK(!holder->HasFixedTypedArrayElements());
     DCHECK(attributes != NONE || !holder->HasFastElements());
     Handle<FixedArrayBase> elements(holder->elements());