Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.h

Index: third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.h
diff --git a/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.h b/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.h
index 161f9786cb93e753a2bf908d47b81f734ff7ef67..5f34430486001a3e926872eba550b5247a41efc5 100644
--- a/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.h
+++ b/third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.h
@@ -49,6 +49,7 @@ class Page;
 class PaintLayer;
 class Region;
 class ScrollableArea;
+class ProgrammaticScrollCoordinator;
 class WebLayerTreeView;
 class WebScrollbarLayer;
 
@@ -134,6 +135,8 @@ class CORE_EXPORT ScrollingCoordinator final
     return m_programmaticScrollAnimatorTimeline.get();
   }
 
+  ProgrammaticScrollCoordinator* programmaticScrollCoordinator();
+
   // For testing purposes only. This ScrollingCoordinator is reused between
   // layout test, and must be reset for the results to be valid.
   void reset();
@@ -186,6 +189,8 @@ class CORE_EXPORT ScrollingCoordinator final
   bool m_wasFrameScrollable;
 
   MainThreadScrollingReasons m_lastMainThreadScrollingReasons;
+
+  Member<ProgrammaticScrollCoordinator> m_programmaticScrollCoordinator;
 };
 
 }  // namespace blink