Oilpan: Add free list profiler.

Source/platform/heap/ThreadState.h

Index: Source/platform/heap/ThreadState.h
diff --git a/Source/platform/heap/ThreadState.h b/Source/platform/heap/ThreadState.h
index 9942dce93c46bacc597a393d8ba6fe2d943e411c..66b2033202a0a464e24c74e5156f0597d38a05da 100644
--- a/Source/platform/heap/ThreadState.h
+++ b/Source/platform/heap/ThreadState.h
@@ -529,6 +529,8 @@ public:
     };
 
     void snapshot();
+
+    void snapshotFreeListIfNecessary();
 #endif
 
     void pushWeakPointerCallback(void*, WeakPointerCallback);
@@ -613,6 +615,10 @@ private:
     void unregisterPreFinalizerInternal(void*);
     void invokePreFinalizers(Visitor&);
 
+#if ENABLE(GC_PROFILING)
+    void snapshotFreeList();
+#endif
+
     static WTF::ThreadSpecific<ThreadState*>* s_threadSpecific;
     static uintptr_t s_mainThreadStackStart;
     static uintptr_t s_mainThreadUnderestimatedStackSize;
@@ -660,6 +666,10 @@ private:
 #endif
 
     Vector<PageMemoryRegion*> m_allocatedRegionsSinceLastGC;
+
+#if ENABLE(GC_PROFILING)
+    double m_nextFreeListSnapshotTime;
+#endif
 };
 
 template<ThreadAffinity affinity> class ThreadStateFor;