Oilpan: Clean up code around GC heuristics

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 682 matching lines @@
     bool shouldForceConservativeGC();
     // estimatedRemovalRatio is the estimated ratio of objects that will be no
     // longer necessary due to the navigation.
     bool shouldSchedulePageNavigationGC(float estimatedRemovalRatio);
 
     // Internal helper for GC policy handling code. Returns true if
     // an urgent conservative GC is now needed due to memory pressure.
     bool shouldForceMemoryPressureGC();
     size_t estimatedLiveObjectSize();
     size_t currentObjectSize();
+    double heapGrowingRate();
+    bool judgeGCThreshold(size_t allocatedObjectSizeThreshold, double heapGrowingRateThreshold);
 
     void runScheduledGC(StackState);
 
     void eagerSweep();
 
 #if defined(ADDRESS_SANITIZER)
     void poisonEagerHeap(Poisoning);
     void poisonAllHeaps();
 #endif
 
@@ skipping 106 matching lines @@
 };
 
 template<> class ThreadStateFor<AnyThread> {
 public:
     static ThreadState* state() { return ThreadState::current(); }
 };
 
 } // namespace blink
 
 #endif // ThreadState_h