Add a helper for implementing Promise-valued properties.

Source/bindings/core/v8/ScriptPromisePropertyBase.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 ScriptPromisePropertyBase_h
+#define ScriptPromisePropertyBase_h
+
+#include "bindings/core/v8/ScopedPersistent.h"
+#include "bindings/core/v8/ScriptPromise.h"
+#include "bindings/core/v8/ScriptPromiseProperties.h"
+#include "core/dom/ContextLifecycleObserver.h"
+#include "wtf/RefCounted.h"
+#include <v8.h>
+
+namespace WebCore {
+
+class ExecutionContext;
+
+class ScriptPromisePropertyBase : public ContextLifecycleObserver, public RefCounted<ScriptPromisePropertyBase> {
+public:
+    virtual ~ScriptPromisePropertyBase();
+
+    enum Name {
+#define P(Name) Name
+        SCRIPT_PROMISE_PROPERTIES(P)
+#undef P
+    };
+
+    enum State {
+        Pending,
+        Resolved,
+        Rejected,
+    };
+    State state() const { return m_state; }
+
+    ScriptPromise promise(DOMWrapperWorld&);
+
+protected:
+    ScriptPromisePropertyBase(ExecutionContext*, Name);
+
+    void resolveOrReject(State targetState);
+
+    // ScriptPromiseProperty overrides these to wrap the holder,
+    // rejected value and resolved value. The
+    // ScriptPromisePropertyBase caller will enter the V8Context for
+    // the property's execution context and the world it is
+    // creating/settling promises in; the implementation should use
+    // this context.
+    virtual v8::Handle<v8::Object> holder(v8::Handle<v8::Object> creationContext, v8::Isolate*) = 0;
+    virtual v8::Handle<v8::Value> resolvedValue(v8::Handle<v8::Object> creationContext, v8::Isolate*) = 0;
+    virtual v8::Handle<v8::Value> rejectedValue(v8::Handle<v8::Object> creationContext, v8::Isolate*) = 0;
+
+private:
+    void resolveOrRejectInternal(v8::Handle<v8::Promise::Resolver>);
+
+    v8::Handle<v8::String> promiseName();
+    v8::Handle<v8::String> resolverName();
+
+    v8::Isolate* m_isolate;
+    Name m_name;
+    State m_state;
+
+    // FIXME: When isolated worlds are supported replace this with a
+    // set of wrappers.
+    ScopedPersistent<v8::Object> m_mainWorldWrapper;
+};
+
+} // namespace WebCore
+
+#endif // ScriptPromisePropertyBase_h