Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/layout/ScrollAlignment.cpp

Index: third_party/WebKit/Source/core/layout/ScrollAlignment.cpp
diff --git a/third_party/WebKit/Source/core/layout/ScrollAlignment.cpp b/third_party/WebKit/Source/core/layout/ScrollAlignment.cpp
index 1f162fb1f3e2c68d94db4a215a19cd7e25b52f89..c97847e736b1e68483390f5625bf3b5de40a8ab4 100644
--- a/third_party/WebKit/Source/core/layout/ScrollAlignment.cpp
+++ b/third_party/WebKit/Source/core/layout/ScrollAlignment.cpp
@@ -54,10 +54,17 @@ const ScrollAlignment ScrollAlignment::alignToEdgeIfNeeded = {
     ScrollAlignmentClosestEdge};
 const ScrollAlignment ScrollAlignment::alignCenterAlways = {
     ScrollAlignmentCenter, ScrollAlignmentCenter, ScrollAlignmentCenter};
+const ScrollAlignment ScrollAlignment::alignClosestEdgeAlways = {
+    ScrollAlignmentClosestEdge, ScrollAlignmentClosestEdge,
+    ScrollAlignmentClosestEdge};
 const ScrollAlignment ScrollAlignment::alignTopAlways = {
     ScrollAlignmentTop, ScrollAlignmentTop, ScrollAlignmentTop};
 const ScrollAlignment ScrollAlignment::alignBottomAlways = {
     ScrollAlignmentBottom, ScrollAlignmentBottom, ScrollAlignmentBottom};
+const ScrollAlignment ScrollAlignment::alignLeftAlways = {
+    ScrollAlignmentLeft, ScrollAlignmentLeft, ScrollAlignmentLeft};
+const ScrollAlignment ScrollAlignment::alignRightAlways = {
+    ScrollAlignmentRight, ScrollAlignmentRight, ScrollAlignmentRight};
 
 #define MIN_INTERSECT_FOR_REVEAL 32