Revert of [SharedArrayBuffer] Prevent SharedArrayBuffer being used in Web APIs

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

Index: third_party/WebKit/Source/core/dom/NotShared.h
diff --git a/third_party/WebKit/Source/core/dom/NotShared.h b/third_party/WebKit/Source/core/dom/NotShared.h
deleted file mode 100644
index 69173aaea4610677a9fcc4a8d9ea73971f742986..0000000000000000000000000000000000000000
--- a/third_party/WebKit/Source/core/dom/NotShared.h
+++ /dev/null
@@ -1,68 +0,0 @@
-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef NotShared_h
-#define NotShared_h
-
-// A wrapper template type that is used to ensure that a TypedArray is not
-// backed by a SharedArrayBuffer.
-//
-// Typically this is used as an annotation on C++ functions that are called by
-// the bindings layer, e.g.:
-//
-//   void Foo(NotShared<DOMUint32Array> param) {
-//     DOMUint32Array* array = param.View();
-//     ...
-//   }
-
-#include "platform/heap/Handle.h"
-
-namespace blink {
-
-template <typename T>
-class NotShared {
-  STACK_ALLOCATED();
-
- public:
-  using TypedArrayType = T;
-
-  NotShared() {}
-
-  explicit NotShared(T* typedArray) : typed_array_(typedArray) {
-    DCHECK(!(typedArray && typedArray->View()->IsShared()));
-  }
-  NotShared(const NotShared& other) = default;
-  template <typename U>
-  NotShared(const NotShared<U>& other) : typed_array_(other.View()) {}
-  template <typename U>
-  NotShared(const Member<U>& other) {
-    DCHECK(!other->View()->IsShared());
-    typed_array_ = other.Get();
-  }
-
-  NotShared& operator=(const NotShared& other) = default;
-  template <typename U>
-  NotShared& operator=(const NotShared<U>& other) {
-    typed_array_ = other.View();
-    return *this;
-  }
-
-  T* View() const { return typed_array_.Get(); }
-
-  bool operator!() const { return !typed_array_; }
-  explicit operator bool() const { return !!typed_array_; }
-
- private:
-  // Must use an untraced member here since this object may be constructed on a
-  // thread without a ThreadState (e.g. an Audio worklet). It is safe in that
-  // case because the pointed-to ArrayBuffer is being kept alive another way
-  // (e.g. CrossThreadPersistent).
-  //
-  // TODO(binji): update to using Member, see crbug.com/710295.
-  UntracedMember<T> typed_array_;
-};
-
-}  // namespace blink
-
-#endif  // NotShared_h