Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/frame/RootFrameViewport.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef RootFrameViewport_h
 #define RootFrameViewport_h
 
 #include "core/CoreExport.h"
 #include "platform/scroll/ScrollableArea.h"
 
@@ skipping 42 matching lines @@
   void DidUpdateVisualViewport();
 
   // ScrollableArea Implementation
   bool IsRootFrameViewport() const override { return true; }
   void SetScrollOffset(const ScrollOffset&,
                        ScrollType,
                        ScrollBehavior = kScrollBehaviorInstant) override;
   LayoutRect ScrollIntoView(const LayoutRect& rect_in_content,
                             const ScrollAlignment& align_x,
                             const ScrollAlignment& align_y,
-                            ScrollType = kProgrammaticScroll) override;
+                            ScrollType = kProgrammaticScroll,
+                            bool is_smooth = false) override;
   IntRect VisibleContentRect(
       IncludeScrollbarsInRect = kExcludeScrollbars) const override;
   bool ShouldUseIntegerScrollOffset() const override;
   bool IsActive() const override;
   int ScrollSize(ScrollbarOrientation) const override;
   bool IsScrollCornerVisible() const override;
   IntRect ScrollCornerRect() const override;
   void UpdateScrollOffset(const ScrollOffset&, ScrollType) override;
   IntSize ScrollOffsetInt() const override;
   ScrollOffset GetScrollOffset() const override;
   IntSize MinimumScrollOffsetInt() const override;
   IntSize MaximumScrollOffsetInt() const override;
   ScrollOffset MaximumScrollOffset() const override;
   IntSize ContentsSize() const override;
   bool ScrollbarsCanBeActive() const override;
   IntRect ScrollableAreaBoundingBox() const override;
   bool UserInputScrollable(ScrollbarOrientation) const override;
   bool ShouldPlaceVerticalScrollbarOnLeft() const override;
+  bool ScheduleAnimation() override;

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

Not sure why this wasn't implemented. It was returning false and preventing the
viewport from scrolling

[bokan, 2017/05/15 17:15:27]

Acknowledged.

   void ScrollControlWasSetNeedsPaintInvalidation() override;
   GraphicsLayer* LayerForContainer() const override;
   GraphicsLayer* LayerForScrolling() const override;
   GraphicsLayer* LayerForHorizontalScrollbar() const override;
   GraphicsLayer* LayerForVerticalScrollbar() const override;
   GraphicsLayer* LayerForScrollCorner() const override;
   int HorizontalScrollbarHeight(
       OverlayScrollbarClipBehavior =
           kIgnorePlatformOverlayScrollbarSize) const override;
   int VerticalScrollbarWidth(
       OverlayScrollbarClipBehavior =
           kIgnorePlatformOverlayScrollbarSize) const override;
   ScrollResult UserScroll(ScrollGranularity, const FloatSize&) override;
   bool ScrollAnimatorEnabled() const override;
   PlatformChromeClient* GetChromeClient() const override;
+  SmoothScrollSequencer* GetSmoothScrollSequencer() const override;
   void ServiceScrollAnimations(double) override;
   void UpdateCompositorScrollAnimations() override;
   void CancelProgrammaticScrollAnimation() override;
   ScrollBehavior ScrollBehaviorStyle() const override;
   void ClearScrollableArea() override;
   LayoutBox* GetLayoutBox() const override;
   FloatQuad LocalToVisibleContentQuad(const FloatQuad&,
                                       const LayoutObject*,
                                       unsigned = 0) const final;
   RefPtr<WebTaskRunner> GetTimerTaskRunner() const final;
@@ skipping 27 matching lines @@
 
 DEFINE_TYPE_CASTS(RootFrameViewport,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->IsRootFrameViewport(),
                   scrollableArea.IsRootFrameViewport());
 
 }  // namespace blink
 
 #endif  // RootFrameViewport_h