Expose InlineTextBoxes in the accessibility tree.

Source/core/rendering/AbstractInlineTextBox.h

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+ */
+
+#ifndef AbstractInlineTextBox_h
+#define AbstractInlineTextBox_h
+
+#include "core/dom/Range.h"
+#include "core/rendering/InlineTextBox.h"
+#include "core/rendering/RenderText.h"
+#include "wtf/HashMap.h"
+#include "wtf/RefPtr.h"
+
+namespace WebCore {
+
+class InlineTextBox;
+
+enum AbstractInlineTextBoxDirection {
+    AbstractInlineTextBoxDirectionLR,

[eseidel, 2013/10/17 18:43:26]

AbstractLeftToRight,
AbstractRightToLeft,
AbstractTopToBottom,
maybe?

Donno. Seems like we're spending a lot of characters on the prefix and not much
on the content. :)  But I'm not wedded to any particular naming scheme.

I'm also OK with this just using existing enums if they fit.  The isolation
layer is more about isolating AX from object liftime troubles than it is from
keeping ABI compatibility, etc.

[dmazzoni, 2013/10/17 20:39:20]

Spelling out LeftToRight, etc. sounds good but "Abstract" as the prefix seems
unclear. How about I move it inside the class? That will make it a lot cleaner.
I can't find an existing enum that expresses this semantically - normally LTR
and RTL are a different enum than TB vs BT.

+    AbstractInlineTextBoxDirectionRL,
+    AbstractInlineTextBoxDirectionTB,
+    AbstractInlineTextBoxDirectionBT
+};
+
+// High-level abstraction of InlineTextBox to allow the accessibility module to
+// get information about InlineTextBoxes without tight coupling.
+class AbstractInlineTextBox : public RefCounted<AbstractInlineTextBox> {
+private:
+    AbstractInlineTextBox(RenderText* renderText, InlineTextBox* inlineTextBox)
+        : m_renderText(renderText)
+        , m_inlineTextBox(inlineTextBox)
+    {
+    }
+
+    static PassRefPtr<AbstractInlineTextBox> getOrCreate(RenderText*, InlineTextBox*);
+    static void willDestroy(InlineTextBox*);
+
+    friend class RenderText;
+    friend class InlineTextBox;
+
+public:
+    struct WordBoundaries {
+        WordBoundaries(int startIndex, int endIndex) : startIndex(startIndex), endIndex(endIndex) { }
+        int startIndex;
+        int endIndex;
+    };
+
+    RenderText* renderText() const { return m_renderText; }
+
+    void detach();
+
+    PassRefPtr<AbstractInlineTextBox> nextInlineTextBox() const;
+    LayoutRect bounds() const;
+    unsigned start() const;
+    unsigned len() const;
+    AbstractInlineTextBoxDirection direction() const;
+    void characterWidths(Vector<float>&) const;
+    void wordBoundaries(Vector<WordBoundaries>&) const;
+    String text() const;
+
+private:
+    RenderText* m_renderText;

[eseidel, 2013/10/17 18:43:26]

I might add a comment like:
// These are weak pointers.  ~InlineTextBox() notifies us of its destruction.
// We assume that RenderText can never be destroyed *before* its InlineTextBoxes
// and depend on ~InlineTextBox for clearing the RenderText* too.

The exact wording is up to you, just to make the lifetime assumptions clear.

[dmazzoni, 2013/10/17 20:39:20]

Done.

+    InlineTextBox* m_inlineTextBox;
+
+    static HashMap<InlineTextBox*, RefPtr<AbstractInlineTextBox> >* gAbstractInlineTextBoxMap;
+};
+
+} // namespace WebCore
+
+#endif // AbstractInlineTextBox_h