Invalidate paint of tickmarks on document change

Source/web/WebLocalFrameImpl.h

Index: Source/web/WebLocalFrameImpl.h
diff --git a/Source/web/WebLocalFrameImpl.h b/Source/web/WebLocalFrameImpl.h
index 5e1a14d4fc0120a4a6dd30d6402d949c084aeb54..7868f222893d54f68c5c37af9a1cc6609a54c276 100644
--- a/Source/web/WebLocalFrameImpl.h
+++ b/Source/web/WebLocalFrameImpl.h
@@ -324,12 +324,6 @@ public:
     // Otherwise creates it and then returns.
     TextFinder& ensureTextFinder();
 
-    // Invalidates vertical scrollbar only.
-    void invalidateScrollbar() const;
-
-    // Invalidates both content area and the scrollbar.
-    void invalidateAll() const;
-

[Xianzhu, 2015/04/17 18:25:03]

These were for TextFinder only. Now TextFinder uses
FrameView::invalidatePaintOfTickmarks() instead. Now the fact that we are
painting tickmarks on vertical scrollbar is contained in core)

invalidateAll() is no longer used. The logic of it is also incorrect for
slimming paint.

     // Returns a hit-tested VisiblePosition for the given point
     VisiblePosition visiblePositionForViewportPoint(const WebPoint&);