Implement Element.scrollIntoView for scroll-behavior: smooth.

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

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 29ddba69decec3a8f4fbbd0b60c08dd5bb9df356..1885bb75dde5cc950285721b189476f5f8331d4e 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -2060,6 +2060,14 @@ HostWindow* FrameView::getHostWindow() const {
   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())
@@ -4457,16 +4465,23 @@ Widget* FrameView::getWidget() {
 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;