Implement Element.scrollIntoView for scroll-behavior: smooth.

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

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 41 matching lines @@
     kScrollAlignmentClosestEdge};
 const ScrollAlignment ScrollAlignment::kAlignToEdgeIfNeeded = {
     kScrollAlignmentNoScroll, kScrollAlignmentClosestEdge,
     kScrollAlignmentClosestEdge};
 const ScrollAlignment ScrollAlignment::kAlignCenterAlways = {
     kScrollAlignmentCenter, kScrollAlignmentCenter, kScrollAlignmentCenter};
 const ScrollAlignment ScrollAlignment::kAlignTopAlways = {
     kScrollAlignmentTop, kScrollAlignmentTop, kScrollAlignmentTop};
 const ScrollAlignment ScrollAlignment::kAlignBottomAlways = {
     kScrollAlignmentBottom, kScrollAlignmentBottom, kScrollAlignmentBottom};
+const ScrollAlignment ScrollAlignment::kAlignLeftAlways = {
+    kScrollAlignmentLeft, kScrollAlignmentLeft, kScrollAlignmentLeft};
+const ScrollAlignment ScrollAlignment::kAlignRightAlways = {
+    kScrollAlignmentRight, kScrollAlignmentRight, kScrollAlignmentRight};
 
 #define MIN_INTERSECT_FOR_REVEAL 32
 
 LayoutRect ScrollAlignment::GetRectToExpose(const LayoutRect& visible_rect,
                                             const LayoutRect& expose_rect,
                                             const ScrollAlignment& align_x,
                                             const ScrollAlignment& align_y) {
   // Prevent degenerate cases by giving the visible rect a minimum non-0 size.
   LayoutRect non_zero_visible_rect(visible_rect);
   LayoutUnit minimum_layout_unit;
@@ skipping 96 matching lines @@
   else if (scroll_y == kScrollAlignmentCenter)
     y = expose_rect.Y() +
         (expose_rect.Height() - non_zero_visible_rect.Height()) / 2;
   else
     y = expose_rect.Y();
 
   return LayoutRect(LayoutPoint(x, y), non_zero_visible_rect.Size());
 }
 
 }  // namespace blink