remove code from (dead) SK_SUPPORT_LEGACY_PIXELREF_UNFLATTENABLE flag

Source/platform/graphics/test/MockDiscardablePixelRef.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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 42 matching lines @@
         virtual bool allocPixelRef(SkBitmap* dst, SkColorTable* ct) SK_OVERRIDE {
             const SkImageInfo& info = dst->info();
             if (kUnknown_SkColorType == info.colorType())
                 return false;
             SkAutoTUnref<SkPixelRef> pr(new MockDiscardablePixelRef(info, dst->rowBytes()));
             dst->setPixelRef(pr);
             return true;
         }
     };
 
-#ifdef SK_SUPPORT_LEGACY_PIXELREF_UNFLATTENABLE
-    SK_DECLARE_UNFLATTENABLE_OBJECT()
-#endif
-
 protected:
     virtual bool onNewLockPixels(LockRec* rec)
     {
         if (discarded)
             return false;
         m_lockedMemory = &discarded;
         rec->fPixels = m_lockedMemory;
         rec->fColorTable = 0;
         rec->fRowBytes = m_rowBytes;
         return true;
     }
 
     virtual void onUnlockPixels()
     {
         m_lockedMemory = 0;
     }
 
 private:
     void* m_lockedMemory;
     size_t m_rowBytes;
     bool discarded;
 };
 
 } // namespace WebCore
 
 #endif // MockDiscardablePixelRef_h