IDBObserver: Lifetime Management: Adding Observer

third_party/WebKit/Source/modules/indexeddb/WebIDBObserverImpl.cpp

+// Copyright 2016 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.
+
+#include "modules/indexeddb/WebIDBObserverImpl.h"
+
+#include "modules/indexeddb/IDBObserver.h"
+#include "wtf/PtrUtil.h"
+
+namespace blink {
+
+// static
+std::unique_ptr<WebIDBObserverImpl> WebIDBObserverImpl::create(IDBObserver* observer)
+{
+    return wrapUnique(new WebIDBObserverImpl(observer));
+}
+
+WebIDBObserverImpl::WebIDBObserverImpl(IDBObserver* observer)
+    : m_id(kInvalidObserverId)
+    , m_observer(observer)
+{
+}
+
+// Remove observe call id from IDBObserver.
+WebIDBObserverImpl::~WebIDBObserverImpl()
+{
+    DCHECK_NE(kInvalidObserverId, m_id);

[cmumford, 2016/07/07 19:48:51]

I think this is OK to have a runtime check - not a DCHECK. Just to enable this
class to be created and destroyed w/o calling setId.

[palakj1, 2016/07/07 21:14:48]

replacing this with a if check
if (m_id != kInvalidObserverId)
        m_observer->removeObserver(m_id);

+    m_observer->removeObserver(m_id);
+}
+
+void WebIDBObserverImpl::setId(int32_t id)
+{
+    DCHECK_EQ(kInvalidObserverId, m_id);
+    m_id = id;
+}
+
+} // namespace blink