Ignore redundant calls to ScrollAnchor::save.

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 e31506970d89bad86113bc54d997dcd68892a0ab..a7fa3803accca0898cfc0d15add2e34be2a1309f 100644
--- a/third_party/WebKit/Source/core/layout/ScrollAnchor.h
+++ b/third_party/WebKit/Source/core/layout/ScrollAnchor.h
@@ -110,6 +110,10 @@ private:
     // change since the last layout.  It is recomputed in save(), and used to
     // suppress the adjustment in restore().  More at http://bit.ly/sanaclap.
     bool m_scrollAnchorDisablingStyleChanged;
+
+    // True iff save has been called, and restore has not been called since
+    // the call to save.  (In this state, additional calls to save are ignored.)
+    bool m_saved;

[ojan, 2016/09/01 05:39:48]

Might be nice to explain that this is to deal with multi-pass layout and to have
a TODO to explore changing scroll anchoring to be at frame boundaries and
removing this bool.

[skobes, 2016/09/01 20:47:21]

Done.

 };
 
 } // namespace blink