Nuke WebPassOwnPtr<T> and replace it with std::unique_ptr<T>.

third_party/WebKit/public/platform/WebPassOwnPtr.h

-// Copyright 2015 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 WebPassOwnPtr_h
-#define WebPassOwnPtr_h
-
-#include "public/platform/WebCommon.h"
-#include <cstddef>
-#include <memory>
-
-#if INSIDE_BLINK
-#include "wtf/PassOwnPtr.h"
-#endif
-
-namespace blink {
-
-// WebPassOwnPtr<T> is used to pass a T pointer with ownership from chromium
-// side to blink side. T's definition must be shared among all users
-// (especially between chromium and blink).
-// TODO(yhirano): Migrate to std::unique_ptr once the repository
-// merge is done or C++11 std library is allowed.
-template <typename T>
-class WebPassOwnPtr final {
-public:
-    WebPassOwnPtr() : m_ptr(nullptr) {}
-    WebPassOwnPtr(std::nullptr_t) : m_ptr(nullptr) {}
-    // We need |const| to bind an rvalue. As a result, |m_ptr| needs to be
-    // mutable because we manipulate it.
-    template <typename U>
-    WebPassOwnPtr(const WebPassOwnPtr<U>& o)
-    {
-        m_ptr = o.m_ptr;
-        o.m_ptr = nullptr;
-    }
-    WebPassOwnPtr(const WebPassOwnPtr& o)
-    {
-        m_ptr = o.m_ptr;
-        o.m_ptr = nullptr;
-    }
-    ~WebPassOwnPtr()
-    {
-        delete m_ptr;
-    }
-    WebPassOwnPtr& operator =(const WebPassOwnPtr&) = delete;
-
-#if INSIDE_BLINK
-    PassOwnPtr<T> release()
-    {
-        T* ptr = m_ptr;
-        m_ptr = nullptr;
-        return adoptPtr(ptr);
-    }
-#else
-    operator std::unique_ptr<T>()
-    {
-        T* ptr = m_ptr;
-        m_ptr = nullptr;
-        return std::unique_ptr<T>(ptr);
-    }
-#endif // INSIDE_BLINK
-
-    template <typename U> friend class WebPassOwnPtr;
-    template <typename U> friend WebPassOwnPtr<U> adoptWebPtr(U*);
-
-private:
-    explicit WebPassOwnPtr(T* ptr) : m_ptr(ptr) {}
-
-    // See the constructor comment to see why |mutable| is needed.
-    mutable T* m_ptr;
-};
-
-template <typename T>
-WebPassOwnPtr<T> adoptWebPtr(T* p) { return WebPassOwnPtr<T>(p); }
-
-} // namespace blink
-
-#endif