| // 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 DocumentVisibilityObserver_h |
| #define DocumentVisibilityObserver_h |
| |
| #include "core/CoreExport.h" |
| #include "core/page/PageVisibilityState.h" |
| #include "platform/heap/Handle.h" |
| |
| namespace blink { |
| |
| class Document; |
| |
| class CORE_EXPORT DocumentVisibilityObserver : public WillBeGarbageCollectedMixin { |
| WTF_MAKE_NONCOPYABLE(DocumentVisibilityObserver); |
| public: |
| explicit DocumentVisibilityObserver(Document&); |
| virtual ~DocumentVisibilityObserver(); |
| |
| virtual void didChangeVisibilityState(PageVisibilityState) = 0; |
| virtual void willDetachDocument() = 0; |
| |
| // Classes that inherit Node and DocumentVisibilityObserver must have a |
| // virtual override of Node::didMoveToNewDocument that calls |
| // DocumentVisibilityObserver::setDocument |
| void setObservedDocument(Document&); |
| |
| protected: |
| DECLARE_VIRTUAL_TRACE(); |
| |
| private: |
| void registerObserver(Document&); |
| void unregisterObserver(); |
| |
| RawPtrWillBeMember<Document> m_document; |
| }; |
| |
| } // namespace blink |
| |
| #endif // DocumentVisibilityObserver_h |