[SharedArrayBuffer] Add "AllowShared" extended attribute, used for WebGL

third_party/WebKit/Source/core/dom/DOMArrayBufferView.h

Index: third_party/WebKit/Source/core/dom/DOMArrayBufferView.h
diff --git a/third_party/WebKit/Source/core/dom/DOMArrayBufferView.h b/third_party/WebKit/Source/core/dom/DOMArrayBufferView.h
index bd95bfdc933fe2f9cc318bc9dc31845de4aff4eb..fe318409ff1e46ea5c0b0661a5b66a0eeee4cc66 100644
--- a/third_party/WebKit/Source/core/dom/DOMArrayBufferView.h
+++ b/third_party/WebKit/Source/core/dom/DOMArrayBufferView.h
@@ -69,6 +69,10 @@ class CORE_EXPORT DOMArrayBufferView
   void SetNeuterable(bool flag) { return View()->SetNeuterable(flag); }
   bool IsShared() const { return View()->IsShared(); }
 
+  void* BaseAddressMaybeShared() const {
+    return View()->BaseAddressMaybeShared();
+  }
+
   v8::Local<v8::Object> Wrap(v8::Isolate*,
                              v8::Local<v8::Object> creation_context) override {
     NOTREACHED();