Introduce KeepAliveWhilePending to ScriptPromiseResolverWithContext.

Source/modules/crypto/CrossThreadCryptoResult.h

+// Copyright 2014 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 CrossThreadCryptoResult_h
+#define CrossThreadCryptoResult_h
+
+#include "core/dom/ExceptionCode.h"
+#include "platform/CryptoResult.h"
+#include "public/platform/WebCrypto.h"
+#include "wtf/WeakPtr.h"
+
+namespace WebCore {
+
+// Wrapper around a Promise to notify completion of the crypto operation.
+//
+// CrossThreadCryptoResult<T> inherits CryptoResult, where T must inherit
+// CryptoResult as well.
+// The thread on which CrossThreadCryptoResult was created on is referred to as the
+// "origin thread".
+//
+//  * At creation time there must be an active ExecutionContext.
+//  * The CryptoResult interface must only be called from the origin thread.
+//  * addref() and deref() can be called from any thread.
+template<typename T>
+class CrossThreadCryptoResult FINAL : public CryptoResult {
+public:
+    ~CrossThreadCryptoResult() { }
+
+    static PassRefPtr<CrossThreadCryptoResult> create(WeakPtr<T> result)
+    {
+        return adoptRef(new CrossThreadCryptoResult(result));
+    }
+
+    // CryptoResult implementation
+    virtual void completeWithError(blink::WebCryptoErrorType type, const blink::WebString& message) OVERRIDE
+    {
+        if (m_result)
+            m_result->completeWithError(type, message);
+    }
+    virtual void completeWithBuffer(const blink::WebArrayBuffer& buffer) OVERRIDE
+    {
+        if (m_result)
+            m_result->completeWithBuffer(buffer);
+    }
+    virtual void completeWithBoolean(bool b) OVERRIDE
+    {
+        if (m_result)
+            m_result->completeWithBoolean(b);
+    }
+    virtual void completeWithKey(const blink::WebCryptoKey& key) OVERRIDE
+    {
+        if (m_result)
+            m_result->completeWithKey(key);
+    }
+    virtual void completeWithKeyPair(const blink::WebCryptoKey& publicKey, const blink::WebCryptoKey& privateKey) OVERRIDE
+    {
+        if (m_result)
+            m_result->completeWithKeyPair(publicKey, privateKey);
+    }
+
+private:
+    explicit CrossThreadCryptoResult(WeakPtr<T> result)
+        : m_result(result) { }
+
+    WeakPtr<T> m_result;
+};
+
+} // namespace WebCore
+
+#endif