Reduce ephemeron stack size reservation.

third_party/WebKit/Source/platform/heap/Heap.cpp

 /*
  * 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 92 matching lines @@
 {
     s_heapDoesNotContainCache->flush();
 }
 
 void Heap::init()
 {
     ThreadState::init();
     s_markingStack = new CallbackStack();
     s_postMarkingCallbackStack = new CallbackStack();
     s_globalWeakCallbackStack = new CallbackStack();
-    s_ephemeronStack = new CallbackStack();
+    // Use smallest supported block size for ephemerons.
+    s_ephemeronStack = new CallbackStack(CallbackStack::kMinimalBlockSize);
     s_heapDoesNotContainCache = new HeapDoesNotContainCache();
     s_freePagePool = new FreePagePool();
     s_orphanedPagePool = new OrphanedPagePool();
     s_allocatedSpace = 0;
     s_allocatedObjectSize = 0;
     s_objectSizeAtLastGC = 0;
     s_markedObjectSize = 0;
     s_markedObjectSizeAtLastCompleteSweep = 0;
     s_wrapperCount = 0;
     s_wrapperCountAtLastGC = 0;
@@ skipping 563 matching lines @@
 size_t Heap::s_wrapperCountAtLastGC = 0;
 size_t Heap::s_collectedWrapperCount = 0;
 size_t Heap::s_partitionAllocSizeAtLastGC = 0;
 double Heap::s_estimatedMarkingTimePerByte = 0.0;
 bool Heap::s_isLowEndDevice = false;
 #if ENABLE(ASSERT)
 uint16_t Heap::s_gcGeneration = 0;
 #endif
 
 } // namespace blink