Limit ScrollAnchor to 20 adjustments between user scrolls.

third_party/WebKit/Source/core/layout/ScrollAnchor.h

Index: third_party/WebKit/Source/core/layout/ScrollAnchor.h
diff --git a/third_party/WebKit/Source/core/layout/ScrollAnchor.h b/third_party/WebKit/Source/core/layout/ScrollAnchor.h
index 0847701788399f3293dd5eeee4c35101e104469f..df5d4c45e3a8151374c8bae0c36cbc4fae4201ca 100644
--- a/third_party/WebKit/Source/core/layout/ScrollAnchor.h
+++ b/third_party/WebKit/Source/core/layout/ScrollAnchor.h
@@ -121,6 +121,9 @@ private:
     // True iff the last adjustment was the exact opposite of the one before it.
     // A bounce suggests a circular interaction with a scroll event handler.
     bool m_hasBounced;
+
+    // Number of adjustments made since the last clear().
+    int m_adjustmentCount;
 };
 
 } // namespace blink