Implement direct allocation in old data space infrastructure.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index d26c38476acf699adb70146d69f719a611d9bfd0..16602f5451987db2c021d8da90f609481e9ac9b2 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -597,6 +597,13 @@ class Heap {
     return old_pointer_space_->allocation_limit_address();
   }
 
+  Address* OldDataSpaceAllocationTopAddress() {
+    return old_data_space_->allocation_top_address();
+  }
+  Address* OldDataSpaceAllocationLimitAddress() {
+    return old_data_space_->allocation_limit_address();
+  }
+
   // Uncommit unused semi space.
   bool UncommitFromSpace() { return new_space_.UncommitFromSpace(); }
 
@@ -1326,6 +1333,10 @@ class Heap {
   inline bool InOldPointerSpace(Address address);
   inline bool InOldPointerSpace(Object* object);
 
+  // Returns whether the object resides in old data space.
+  inline bool InOldDataSpace(Address address);
+  inline bool InOldDataSpace(Object* object);
+
   // Checks whether an address/object in the heap (including auxiliary
   // area and unused area).
   bool Contains(Address addr);