Revert of Remove ExternalArray, derived types, and element kinds

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index 5babfdf1a7f434ce341a735b9daf1f9ee61813a5..b68895fbc6d27745e4dd8e1ca6bc71674b772ef9 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -78,6 +78,9 @@
       break;
 
 #define VERIFY_TYPED_ARRAY(Type, type, TYPE, ctype, size)                      \
+    case EXTERNAL_##TYPE##_ARRAY_TYPE:                                         \
+      External##Type##Array::cast(this)->External##Type##ArrayVerify();        \
+      break;                                                                   \
     case FIXED_##TYPE##_ARRAY_TYPE:                                            \
       Fixed##Type##Array::cast(this)->FixedTypedArrayVerify();                 \
       break;
@@ -233,17 +236,21 @@
 }
 
 
+#define EXTERNAL_ARRAY_VERIFY(Type, type, TYPE, ctype, size)                  \
+  void External##Type##Array::External##Type##ArrayVerify() {                 \
+    CHECK(IsExternal##Type##Array());                                         \
+  }
+
+TYPED_ARRAYS(EXTERNAL_ARRAY_VERIFY)
+#undef EXTERNAL_ARRAY_VERIFY
+
+
 template <class Traits>
 void FixedTypedArray<Traits>::FixedTypedArrayVerify() {
   CHECK(IsHeapObject() &&
         HeapObject::cast(this)->map()->instance_type() ==
             Traits::kInstanceType);
-  if (base_pointer() == this) {
-    CHECK(external_pointer() ==
-          ExternalReference::fixed_typed_array_base_data_offset().address());
-  } else {
-    CHECK(base_pointer() == nullptr);
-  }
+  CHECK(base_pointer() == this);
 }
 
 
@@ -1089,6 +1096,7 @@
     }
 
 #define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size)                       \
+    case EXTERNAL_##TYPE##_ELEMENTS:                                          \
     case TYPE##_ELEMENTS:
 
     TYPED_ARRAYS(TYPED_ARRAY_CASE)