Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/platform/scroll/ScrollableArea.h

 /*
  * Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 35 matching lines @@
 class CompositorAnimationTimeline;
 class GraphicsLayer;
 class HostWindow;
 class LayoutBox;
 class LayoutObject;
 class PaintLayer;
 class ProgrammaticScrollAnimator;
 struct ScrollAlignment;
 class ScrollAnchor;
 class ScrollAnimatorBase;
+class SmoothScrollSequencer;
 class CompositorAnimationTimeline;
 
 enum IncludeScrollbarsInRect {
   ExcludeScrollbars,
   IncludeScrollbars,
 };
 
 class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin,
                                        public WebLayerScrollClient {
   WTF_MAKE_NONCOPYABLE(ScrollableArea);
 
  public:
   static int pixelsPerLineStep(HostWindow*);
   static float minFractionToStepWhenPaging();
   static int maxOverlapBetweenPages();
 
   // Convert a non-finite scroll value (Infinity, -Infinity, NaN) to 0 as
   // per http://dev.w3.org/csswg/cssom-view/#normalize-non_finite-values.
   static float normalizeNonFiniteScroll(float value) {
     return std::isfinite(value) ? value : 0.0;
   }
 
   // The window that hosts the ScrollableArea. The ScrollableArea will
   // communicate scrolls and repaints to the host window in the window's
   // coordinate space.
   virtual HostWindow* getHostWindow() const { return 0; }
 
+  virtual SmoothScrollSequencer* getSmoothScrollSequencer() const { return 0; }

[bokan, 2017/04/07 15:56:52]

nit: return nullptr

[sunyunjia, 2017/05/12 18:40:25]

Done.

+
   virtual ScrollResult userScroll(ScrollGranularity, const ScrollOffset&);
 
   virtual void setScrollOffset(const ScrollOffset&,
                                ScrollType,
                                ScrollBehavior = ScrollBehaviorInstant);
   virtual void scrollBy(const ScrollOffset&,
                         ScrollType,
                         ScrollBehavior = ScrollBehaviorInstant);
   void setScrollOffsetSingleAxis(ScrollbarOrientation,
                                  float,
                                  ScrollType,
                                  ScrollBehavior = ScrollBehaviorInstant);
 
   // Scrolls the area so that the given rect, given in the document's content
   // coordinates, such that it's visible in the area. Returns the new location
   // of the input rect relative once again to the document.
   // Note, in the case of a Document container, such as FrameView, the output
   // will always be the input rect since scrolling it can't change the location
   // of content relative to the document, unlike an overflowing element.
   virtual LayoutRect scrollIntoView(const LayoutRect& rectInContent,
                                     const ScrollAlignment& alignX,
                                     const ScrollAlignment& alignY,
-                                    ScrollType = ProgrammaticScroll);
+                                    ScrollType = ProgrammaticScroll,
+                                    bool isSmooth = false);
 
   static bool scrollBehaviorFromString(const String&, ScrollBehavior&);
 
   void contentAreaWillPaint() const;
   void mouseEnteredContentArea() const;
   void mouseExitedContentArea() const;
   void mouseMovedInContentArea() const;
   void mouseEnteredScrollbar(Scrollbar&);
   void mouseExitedScrollbar(Scrollbar&);
   void mouseCapturedScrollbar();
@@ skipping 345 matching lines @@
   // vertical-lr / ltr            NO                      NO
   // vertical-lr / rtl            NO                      YES
   // vertical-rl / ltr            YES                     NO
   // vertical-rl / rtl            YES                     YES
   IntPoint m_scrollOrigin;
 };
 
 }  // namespace blink
 
 #endif  // ScrollableArea_h