Refactor the Heap into ThreadHeap to prepare for per thread heaps

third_party/WebKit/Source/platform/WebThreadSupportingGC.h

Index: third_party/WebKit/Source/platform/WebThreadSupportingGC.h
diff --git a/third_party/WebKit/Source/platform/WebThreadSupportingGC.h b/third_party/WebKit/Source/platform/WebThreadSupportingGC.h
index 3e057918eb30b22c2026c90db06fc0d54e4e5997..f8f9ddda833bc4b2245e361b39f6a9944007f8ab 100644
--- a/third_party/WebKit/Source/platform/WebThreadSupportingGC.h
+++ b/third_party/WebKit/Source/platform/WebThreadSupportingGC.h
@@ -29,8 +29,8 @@ class PLATFORM_EXPORT WebThreadSupportingGC final {
     USING_FAST_MALLOC(WebThreadSupportingGC);
     WTF_MAKE_NONCOPYABLE(WebThreadSupportingGC);
 public:
-    static PassOwnPtr<WebThreadSupportingGC> create(const char* name);
-    static PassOwnPtr<WebThreadSupportingGC> createForThread(WebThread*);
+    static PassOwnPtr<WebThreadSupportingGC> create(const char* name, ThreadState::PerThreadHeapState);
+    static PassOwnPtr<WebThreadSupportingGC> createForThread(WebThread*, ThreadState::PerThreadHeapState);
     ~WebThreadSupportingGC();
 
     void postTask(const WebTraceLocation& location, WebTaskRunner::Task* task)
@@ -68,7 +68,7 @@ public:
     }
 
 private:
-    WebThreadSupportingGC(const char* name, WebThread*);
+    WebThreadSupportingGC(const char* name, WebThread*, ThreadState::PerThreadHeapState);
 
     OwnPtr<GCTaskRunner> m_gcTaskRunner;
 
@@ -77,6 +77,7 @@ private:
     // existing thread via createForThread().
     WebThread* m_thread = nullptr;
     OwnPtr<WebThread> m_owningThread;
+    bool m_perThreadHeapEnabled;
 };
 
 }