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 LayoutBox;
 class LayoutObject;
 class PaintLayer;
 class PlatformChromeClient;
 class ProgrammaticScrollAnimator;
 struct ScrollAlignment;
 class ScrollAnchor;
 class ScrollAnimatorBase;
+class SmoothScrollSequencer;
 class CompositorAnimationTimeline;
 
 enum IncludeScrollbarsInRect {
   kExcludeScrollbars,
   kIncludeScrollbars,
 };
 
 class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin,
                                        public WebLayerScrollClient {
   WTF_MAKE_NONCOPYABLE(ScrollableArea);
 
  public:
   static int PixelsPerLineStep(PlatformChromeClient*);
   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;
   }
 
   virtual PlatformChromeClient* GetChromeClient() const { return 0; }
 
+  virtual SmoothScrollSequencer* GetSmoothScrollSequencer() const {
+    return nullptr;
+  }
+
   virtual ScrollResult UserScroll(ScrollGranularity, const ScrollOffset&);
 
   virtual void SetScrollOffset(const ScrollOffset&,
                                ScrollType,
                                ScrollBehavior = kScrollBehaviorInstant);
   virtual void ScrollBy(const ScrollOffset&,
                         ScrollType,
                         ScrollBehavior = kScrollBehaviorInstant);
   void SetScrollOffsetSingleAxis(ScrollbarOrientation,
                                  float,
                                  ScrollType,
                                  ScrollBehavior = kScrollBehaviorInstant);
 
   // 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& rect_in_content,
                                     const ScrollAlignment& align_x,
                                     const ScrollAlignment& align_y,
-                                    ScrollType = kProgrammaticScroll);
+                                    ScrollType = kProgrammaticScroll,
+                                    bool is_smooth = false);

[bokan, 2017/05/15 17:15:28]

This has few enough callers, and you always pass it in anyway, that I'd avoid
making it a default parameter.

[sunyunjia, 2017/05/19 16:24:29]

Done.

 
   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 337 matching lines @@
   // vertical-lr / ltr            NO                      NO
   // vertical-lr / rtl            NO                      YES
   // vertical-rl / ltr            YES                     NO
   // vertical-rl / rtl            YES                     YES
   IntPoint scroll_origin_;
 };
 
 }  // namespace blink
 
 #endif  // ScrollableArea_h