Make the full object memory size of a page available for a single allocation.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 44e8cb6e33161393f5d494537a31929181ed44a0..d2713b9cfb67efc4ebaf00e082db12d4a02aac1e 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -779,15 +779,11 @@ class Page : public MemoryChunk {
   // Page size in bytes.  This must be a multiple of the OS page size.
   static const int kPageSize = 1 << kPageSizeBits;
 
-  // Object area size in bytes.
-  static const int kNonCodeObjectAreaSize = kPageSize - kObjectStartOffset;
-
   // Maximum object size that fits in a page. Objects larger than that size
   // are allocated in large object space and are never moved in memory. This
   // also applies to new space allocation, since objects are never migrated
   // from new space to large object space.  Takes double alignment into account.
-  static const int kMaxNonCodeHeapObjectSize =
-      kNonCodeObjectAreaSize - kPointerSize;
+  static const int kMaxNonCodeHeapObjectSize = kPageSize - kObjectStartOffset;
 
   // Page size mask.
   static const intptr_t kPageAlignmentMask = (1 << kPageSizeBits) - 1;
@@ -2013,7 +2009,7 @@ class NewSpacePage : public MemoryChunk {
     (1 << MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING) |
     (1 << MemoryChunk::SCAN_ON_SCAVENGE);
 
-  static const int kAreaSize = Page::kNonCodeObjectAreaSize;
+  static const int kAreaSize = Page::kMaxNonCodeHeapObjectSize;
 
   inline NewSpacePage* next_page() const {
     return static_cast<NewSpacePage*>(next_chunk());
@@ -2673,7 +2669,7 @@ class MapSpace : public PagedSpace {
   virtual void VerifyObject(HeapObject* obj);
 
  private:
-  static const int kMapsPerPage = Page::kNonCodeObjectAreaSize / Map::kSize;
+  static const int kMapsPerPage = Page::kMaxNonCodeHeapObjectSize / Map::kSize;
 
   // Do map space compaction if there is a page gap.
   int CompactionThreshold() {