Explicit management of FrameSelection availability

third_party/WebKit/Source/core/editing/FrameSelection.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 75 matching lines @@
         DoNotUpdateAppearance = 1 << 4,
         DoNotClearStrategy = 1 << 5,
         DoNotAdjustInFlatTree = 1 << 6,
     };
     typedef unsigned SetSelectionOptions; // Union of values in SetSelectionOption and EUserTriggered
     static inline EUserTriggered selectionOptionsToUserTriggered(SetSelectionOptions options)
     {
         return static_cast<EUserTriggered>(options & UserTriggered);
     }
 
+    bool isAvailable() const { return m_document; }
+    const Document& document() const;

[tkent, 2016/06/07 23:41:59]

We should add a comment like |This function must not be called when
!isAvailable()|.

+    Document& document();
     LocalFrame* frame() const { return m_frame; }
     Element* rootEditableElement() const { return selection().rootEditableElement(); }
     Element* rootEditableElementOrDocumentElement() const;
     ContainerNode* rootEditableElementOrTreeScopeRootNode() const;
 
     bool hasEditableStyle() const { return selection().hasEditableStyle(); }
     bool isContentEditable() const { return selection().isContentEditable(); }
     bool isContentRichlyEditable() const { return selection().isContentRichlyEditable(); }
 
     void moveTo(const VisiblePosition&, EUserTriggered = NotUserTriggered, CursorAlignOnScroll = CursorAlignOnScroll::IfNeeded);
     void moveTo(const VisiblePosition&, const VisiblePosition&, EUserTriggered = NotUserTriggered);
     void moveTo(const Position&, TextAffinity);
 
     template <typename Strategy>
     const VisibleSelectionTemplate<Strategy>& visibleSelection() const;
 
     const VisibleSelection& selection() const;
     void setSelection(const VisibleSelection&, SetSelectionOptions = CloseTyping | ClearTypingStyle, CursorAlignOnScroll = CursorAlignOnScroll::IfNeeded, TextGranularity = CharacterGranularity);
     void setSelection(const VisibleSelectionInFlatTree&, SetSelectionOptions = CloseTyping | ClearTypingStyle, CursorAlignOnScroll = CursorAlignOnScroll::IfNeeded, TextGranularity = CharacterGranularity);
     // TODO(yosin) We should get rid of two parameters version of
     // |setSelection()| to avoid conflict of four parameters version.
     void setSelection(const VisibleSelection& selection, TextGranularity granularity) { setSelection(selection, CloseTyping | ClearTypingStyle, CursorAlignOnScroll::IfNeeded, granularity); }
     // TODO(yosin) We should get rid of |Range| version of |setSelectedRagne()|
     // for Oilpan.
     bool setSelectedRange(Range*, TextAffinity, SelectionDirectionalMode = SelectionDirectionalMode::NonDirectional, SetSelectionOptions = CloseTyping | ClearTypingStyle);
     bool setSelectedRange(const EphemeralRange&, TextAffinity, SelectionDirectionalMode = SelectionDirectionalMode::NonDirectional, FrameSelection::SetSelectionOptions = CloseTyping | ClearTypingStyle);
     void selectAll();
     void clear();
-    void prepareForDestruction();
 
     // Call this after doing user-triggered selections to make it easy to delete the frame you entirely selected.
     void selectFrameElementInParentIfFullySelected();
 
     bool contains(const LayoutPoint&);
 
     SelectionType getSelectionType() const { return selection().getSelectionType(); }
 
     TextAffinity affinity() const { return selection().affinity(); }
 
@@ skipping 26 matching lines @@
     bool isNone() const { return selection().isNone(); }
     bool isCaret() const { return selection().isCaret(); }
     bool isRange() const { return selection().isRange(); }
     bool isInPasswordField() const;
     bool isDirectional() const { return selection().isDirectional(); }
 
     // If this FrameSelection has a logical range which is still valid, this function return its clone. Otherwise,
     // the return value from underlying VisibleSelection's firstRange() is returned.
     Range* firstRange() const;
 
+    void documentAttached(Document*);
+    void documentDetached(const Document&);
     void nodeWillBeRemoved(Node&);
     void dataWillChange(const CharacterData& node);
     void didUpdateCharacterData(CharacterData*, unsigned offset, unsigned oldLength, unsigned newLength);
     void didMergeTextNodes(const Text& oldNode, unsigned offset);
     void didSplitTextNode(const Text& oldNode);
 
     bool isAppearanceDirty() const;
     void commitAppearanceIfNeeded(LayoutView&);
     void updateAppearance();
     void setCaretVisible(bool caretIsVisible);
@@ skipping 92 matching lines @@
 
     template <typename Strategy>
     VisibleSelectionTemplate<Strategy> validateSelection(const VisibleSelectionTemplate<Strategy>&);
 
     GranularityStrategy* granularityStrategy();
 
     // For unittests
     bool shouldPaintCaretForTesting() const;
     bool isPreviousCaretDirtyForTesting() const;
 
+    Member<Document> m_document;
     Member<LocalFrame> m_frame;
     const Member<PendingSelection> m_pendingSelection;
     const Member<SelectionEditor> m_selectionEditor;
 
     // Used to store base before the adjustment at bidi boundary
     VisiblePosition m_originalBase;
     VisiblePositionInFlatTree m_originalBaseInFlatTree;
     TextGranularity m_granularity;
     LayoutUnit m_xPosForVerticalArrowNavigation;
 
@@ skipping 23 matching lines @@
 }
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const blink::FrameSelection&);
 void showTree(const blink::FrameSelection*);
 #endif
 
 #endif // FrameSelection_h