Oilpan: introduce eager finalization.

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 d44c39c32daa7d57547ba208aebe2b50c0593265..213170db701f44d52e20cb88735a751a38d74add 100644
--- a/Source/platform/heap/ThreadState.h
+++ b/Source/platform/heap/ThreadState.h
@@ -144,11 +144,11 @@ using EphemeronCallback = VisitorCallback;
 #define TypedHeapEnumName(Type) Type##HeapIndex,
 
 enum HeapIndices {
-    NormalPage1HeapIndex = 0,
+    EagerSweepHeapIndex = 0,
+    NormalPage1HeapIndex,
     NormalPage2HeapIndex,
     NormalPage3HeapIndex,
     NormalPage4HeapIndex,
-    EagerSweepHeapIndex,
     Vector1HeapIndex,
     Vector2HeapIndex,
     Vector3HeapIndex,
@@ -161,6 +161,20 @@ enum HeapIndices {
     NumberOfHeaps,
 };
 
+#if defined(ADDRESS_SANITIZER)
+// Heaps can have their object payloads be poisoned, or cleared
+// of their poisoning.
+enum Poisoning {
+    SetPoison,
+    ClearPoison,
+};
+
+enum ObjectsToPoison {
+    UnmarkedOnly,
+    MarkedAndUnmarked,
+};
+#endif
+
 #if ENABLE(GC_PROFILING)
 const size_t numberOfGenerationsToTrack = 8;
 const size_t maxHeapObjectAge = numberOfGenerationsToTrack - 1;
@@ -646,6 +660,11 @@ private:
 
     void eagerSweep();
 
+#if defined(ADDRESS_SANITIZER)
+    void poisonEagerHeap(Poisoning);
+    void poisonAllHeaps();
+#endif
+
     // When ThreadState is detaching from non-main thread its
     // heap is expected to be empty (because it is going away).
     // Perform registered cleanup tasks and garbage collection