Expose scroll containers via accessibility APIs.

Source/modules/accessibility/AXObject.h

Index: Source/modules/accessibility/AXObject.h
diff --git a/Source/modules/accessibility/AXObject.h b/Source/modules/accessibility/AXObject.h
index dfeb0dcd88d0203967f667463a5299ab58ed6454..e024f2b4548753d587845d430e507c6b0eff2340 100644
--- a/Source/modules/accessibility/AXObject.h
+++ b/Source/modules/accessibility/AXObject.h
@@ -675,6 +675,13 @@ public:
     // Selected text.
     virtual PlainTextRange selectedTextRange() const { return PlainTextRange(); }
 
+    // Scrollable containers.
+    bool isScrollableContainer() const;
+    IntPoint scrollOffset() const;
+    IntPoint minimumScrollOffset() const;
+    IntPoint maximumScrollOffset() const;
+    void setScrollOffset(const IntPoint&) const;
+
     // Modify or take an action on an object.
     virtual void increment() { }
     virtual void decrement() { }
@@ -729,7 +736,6 @@ protected:
 
     // If this object itself scrolls, return its ScrollableArea.
     virtual ScrollableArea* getScrollableAreaIfScrollable() const { return 0; }
-    virtual void scrollTo(const IntPoint&) const { }
 
     AccessibilityRole buttonRoleType() const;