Introduce a base pointer field in FixedTypedArrayBase and teach GC about it

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 966954dfda9b4047b0df33719daaa5b43a616b67..a10832f30b182f2776f31be0be91f2745e119596 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -1538,6 +1538,9 @@ HeapObjectContents HeapObject::ContentType() {
   } else if (type == JS_FUNCTION_TYPE) {
     return HeapObjectContents::kMixedValues;
 #endif
+  } else if (type >= FIRST_FIXED_TYPED_ARRAY_TYPE &&
+             type <= LAST_FIXED_TYPED_ARRAY_TYPE) {
+    return HeapObjectContents::kMixedValues;
   } else if (type <= LAST_DATA_TYPE) {
     // TODO(jochen): Why do we claim that Code and Map contain only raw values?
     return HeapObjectContents::kRawValues;
@@ -3877,6 +3880,9 @@ void ExternalFloat64Array::set(int index, double value) {
 }
 
 
+ACCESSORS(FixedTypedArrayBase, base_pointer, Object, kBasePointerOffset)
+
+
 void* FixedTypedArrayBase::DataPtr() {
   return FIELD_ADDR(this, kDataOffset);
 }
@@ -7161,6 +7167,19 @@ void Foreign::ForeignIterateBody() {
 }
 
 
+void FixedTypedArrayBase::FixedTypedArrayBaseIterateBody(ObjectVisitor* v) {
+  v->VisitPointer(
+      reinterpret_cast<Object**>(FIELD_ADDR(this, kBasePointerOffset)));
+}
+
+
+template <typename StaticVisitor>
+void FixedTypedArrayBase::FixedTypedArrayBaseIterateBody() {
+  StaticVisitor::VisitPointer(
+      reinterpret_cast<Object**>(FIELD_ADDR(this, kBasePointerOffset)));
+}
+
+
 void ExternalOneByteString::ExternalOneByteStringIterateBody(ObjectVisitor* v) {
   typedef v8::String::ExternalOneByteStringResource Resource;
   v->VisitExternalOneByteString(