Revert of heap: make array buffer maps disjoint

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index be5044380f584a7a0d82b7f3e584e7173e2f5310..a4ecdf7c79a55d913fe5d9b2eaaae261940eca8e 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -1790,6 +1790,21 @@
   // Called on heap tear-down. Frees all remaining ArrayBuffer backing stores.
   void TearDownArrayBuffers();
 
+  // These correspond to the non-Helper versions.
+  void RegisterNewArrayBufferHelper(std::map<void*, size_t>& live_buffers,
+                                    void* data, size_t length);
+  void UnregisterArrayBufferHelper(
+      std::map<void*, size_t>& live_buffers,
+      std::map<void*, size_t>& not_yet_discovered_buffers, void* data);
+  void RegisterLiveArrayBufferHelper(
+      std::map<void*, size_t>& not_yet_discovered_buffers, void* data);
+  size_t FreeDeadArrayBuffersHelper(
+      Isolate* isolate, std::map<void*, size_t>& live_buffers,
+      std::map<void*, size_t>& not_yet_discovered_buffers);
+  void TearDownArrayBuffersHelper(
+      Isolate* isolate, std::map<void*, size_t>& live_buffers,
+      std::map<void*, size_t>& not_yet_discovered_buffers);
+
   // Record statistics before and after garbage collection.
   void ReportStatisticsBeforeGC();
   void ReportStatisticsAfterGC();