Remove usages of Heap::NewSpaceStart and its external reference

src/heap/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 859 matching lines @@
   // Destroys all memory allocated by the heap.
   void TearDown();
 
   // Returns whether SetUp has been called.
   bool HasBeenSetUp();
 
   // ===========================================================================
   // Getters for spaces. =======================================================
   // ===========================================================================
 
-  // Return the starting address and a mask for the new space.  And-masking an
-  // address with the mask will result in the start address of the new space
-  // for all addresses in either semispace.
-  Address NewSpaceStart() { return new_space_.start(); }
   Address NewSpaceTop() { return new_space_.top(); }
 
   NewSpace* new_space() { return &new_space_; }
   OldSpace* old_space() { return old_space_; }
   OldSpace* code_space() { return code_space_; }
   MapSpace* map_space() { return map_space_; }
   LargeObjectSpace* lo_space() { return lo_space_; }
 
   PagedSpace* paged_space(int idx) {
     switch (idx) {
@@ skipping 1760 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_