Oilpan: Remove ThreadState::statsAfterLastGC().

Source/platform/heap/ThreadState.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 665 matching lines @@
     };
 
     void snapshot();
 #endif
 
     void pushWeakObjectPointerCallback(void*, WeakPointerCallback);
     bool popAndInvokeWeakPointerCallback(Visitor*);
 
     void getStats(HeapStats&);
     HeapStats& stats() { return m_stats; }
-    HeapStats& statsAfterLastGC() { return m_statsAfterLastGC; }
 
     void setupHeapsForTermination();
 
     void registerSweepingTask();
     void unregisterSweepingTask();
 
     // Request to call a pref-finalizer of the target object before the object
     // is destructed.  The class T must have USING_PRE_FINALIZER().  The
     // argument should be |*this|.  Registering a lot of objects affects GC
     // performance.  We should register an object only if the object really
@@ skipping 246 matching lines @@
     // whether the page is part of a terminting thread or
     // if the page is traced after being terminated (orphaned).
     uintptr_t m_terminating : 1;
     uintptr_t m_tracedAfterOrphaned : 1;
     uintptr_t m_promptlyFreedSize : 17; // == blinkPageSizeLog2
 };
 
 }
 
 #endif // ThreadState_h