Refactor the Heap into ThreadHeap to prepare for per thread heaps

third_party/WebKit/Source/platform/heap/BlinkGC.h

Index: third_party/WebKit/Source/platform/heap/BlinkGC.h
diff --git a/third_party/WebKit/Source/platform/heap/BlinkGC.h b/third_party/WebKit/Source/platform/heap/BlinkGC.h
index 688525a1d3873572ad96be47c19950114f3d7897..e7505abdd78c26d08c2060f400b0ece3367f03dd 100644
--- a/third_party/WebKit/Source/platform/heap/BlinkGC.h
+++ b/third_party/WebKit/Source/platform/heap/BlinkGC.h
@@ -34,7 +34,7 @@ using PreFinalizerCallback = bool(*)(void*);
     H(Node)                                 \
     H(CSSValue)
 
-#define TypedHeapEnumName(Type) Type##HeapIndex,
+#define TypedHeapEnumName(Type) Type##ArenaIndex,
 
 class PLATFORM_EXPORT BlinkGC final {
     STATIC_ONLY(BlinkGC);
@@ -80,21 +80,21 @@ public:
     };
 
     enum HeapIndices {
-        EagerSweepHeapIndex = 0,
-        NormalPage1HeapIndex,
-        NormalPage2HeapIndex,
-        NormalPage3HeapIndex,
-        NormalPage4HeapIndex,
-        Vector1HeapIndex,
-        Vector2HeapIndex,
-        Vector3HeapIndex,
-        Vector4HeapIndex,
-        InlineVectorHeapIndex,
-        HashTableHeapIndex,
+        EagerSweepArenaIndex = 0,
+        NormalPage1ArenaIndex,
+        NormalPage2ArenaIndex,
+        NormalPage3ArenaIndex,
+        NormalPage4ArenaIndex,
+        Vector1ArenaIndex,
+        Vector2ArenaIndex,
+        Vector3ArenaIndex,
+        Vector4ArenaIndex,
+        InlineVectorArenaIndex,
+        HashTableArenaIndex,
         FOR_EACH_TYPED_HEAP(TypedHeapEnumName)
-        LargeObjectHeapIndex,
+        LargeObjectArenaIndex,
         // Values used for iteration of heap segments.
-        NumberOfHeaps,
+        NumberOfArenas,
     };
 
 #if defined(ADDRESS_SANITIZER)