Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 2042 matching lines @@
   }
 }
 
 HostWindow* FrameView::getHostWindow() const {
   Page* page = frame().page();
   if (!page)
     return nullptr;
   return &page->chromeClient();
 }
 
+ProgrammaticScrollCoordinator* FrameView::getProgrammaticScrollCoordinator()
+    const {
+  Page* page = frame().page();
+  if (!page)
+    return nullptr;
+  return page->scrollingCoordinator()->programmaticScrollCoordinator();
+}
+
 void FrameView::contentsResized() {
   if (m_frame->isMainFrame() && m_frame->document()) {
     if (TextAutosizer* textAutosizer = m_frame->document()->textAutosizer())
       textAutosizer->updatePageInfoInAllFrames();
   }
 
   ScrollableArea::contentsResized();
   setNeedsLayout();
 }
 
@@ skipping 2377 matching lines @@
   return false;
 }
 
 Widget* FrameView::getWidget() {
   return this;
 }
 
 LayoutRect FrameView::scrollIntoView(const LayoutRect& rectInContent,
                                      const ScrollAlignment& alignX,
                                      const ScrollAlignment& alignY,
-                                     ScrollType scrollType) {
+                                     ScrollType scrollType,
+                                     bool isSmooth) {
   LayoutRect viewRect(visibleContentRect());
   LayoutRect exposeRect =
       ScrollAlignment::getRectToExpose(viewRect, rectInContent, alignX, alignY);
   if (exposeRect != viewRect) {
-    setScrollOffset(
-        ScrollOffset(exposeRect.x().toFloat(), exposeRect.y().toFloat()),
-        scrollType);
+    if (isSmooth) {
+      DCHECK(scrollType != UserScroll);
+      getProgrammaticScrollCoordinator()->queueAnimation(
+          this,
+          ScrollOffset(exposeRect.x().toFloat(), exposeRect.y().toFloat()));

[bokan, 2017/03/28 16:29:53]

Store the ScrollOffset in a variable above, outside the if(isSmooth)/else

[sunyunjia, 2017/04/07 13:53:20]

Done.

+    } else {
+      setScrollOffset(
+          ScrollOffset(exposeRect.x().toFloat(), exposeRect.y().toFloat()),
+          scrollType);
+    }
   }
-
   // Scrolling the FrameView cannot change the input rect's location relative to
   // the document.
   return rectInContent;
 }
 
 IntRect FrameView::scrollCornerRect() const {
   IntRect cornerRect;
 
   if (hasOverlayScrollbars())
     return cornerRect;
@@ skipping 705 matching lines @@
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 LayoutUnit FrameView::caretWidth() const {
   return LayoutUnit(getHostWindow()->windowToViewportScalar(1));
 }
 
 }  // namespace blink