Implement direct allocation in old data space infrastructure.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index fc96662d232154d01942fb93fc42f85861415295..c823c4be2696cf1ed69a348843f1d13d1982f95f 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -1202,6 +1202,20 @@ ExternalReference ExternalReference::old_pointer_space_allocation_limit_address(
 }
 
 
+ExternalReference ExternalReference::old_data_space_allocation_top_address(
+    Isolate* isolate) {
+  return ExternalReference(
+      isolate->heap()->OldDataSpaceAllocationTopAddress());
+}
+
+
+ExternalReference ExternalReference::old_data_space_allocation_limit_address(
+    Isolate* isolate) {
+  return ExternalReference(
+      isolate->heap()->OldDataSpaceAllocationLimitAddress());
+}
+
+
 ExternalReference ExternalReference::handle_scope_level_address(
     Isolate* isolate) {
   return ExternalReference(HandleScope::current_level_address(isolate));