Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/platform/scroll/ProgrammaticScrollCoordinator.cpp

+// Copyright (c) 2017 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.
+#include "platform/scroll/ProgrammaticScrollCoordinator.h"
+
+#include "platform/scroll/ProgrammaticScrollAnimator.h"
+#include "platform/scroll/ScrollableArea.h"
+
+namespace blink {
+
+ProgrammaticScrollCoordinator* ProgrammaticScrollCoordinator::create() {
+  return new ProgrammaticScrollCoordinator();
+}
+
+ProgrammaticScrollCoordinator::ProgrammaticScrollCoordinator() {}
+
+ProgrammaticScrollCoordinator::~ProgrammaticScrollCoordinator() {}
+
+void ProgrammaticScrollCoordinator::queueAnimation(ScrollableArea* scrollable,
+                                                   ScrollOffset offset) {
+  ScrollerAndOffsetPair scrollerOffset(scrollable, offset);
+  m_queue.push_back(scrollerOffset);
+}
+
+void ProgrammaticScrollCoordinator::runQueuedAnimations() {
+  if (!m_queue.empty()) {
+    ScrollerAndOffsetPair scrollerOffset = m_queue.back();
+    ScrollableArea* scrollable = scrollerOffset.first;
+    ScrollOffset offset = scrollerOffset.second;
+    scrollable->programmaticScrollAnimator().animateToOffset(offset);
+  }
+}
+
+void ProgrammaticScrollCoordinator::notifyAnimationFinished() {
+  m_queue.pop_back();
+  if (!m_queue.empty()) {

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

This whole block can be replaced with runQueuedAnimations().

[sunyunjia, 2017/04/07 13:53:21]

Done.

+    ScrollerAndOffsetPair scrollerOffset = m_queue.back();
+    ScrollableArea* scrollable = scrollerOffset.first;
+    ScrollOffset offset = scrollerOffset.second;
+    scrollable->programmaticScrollAnimator().animateToOffset(offset);
+  }
+}
+
+void ProgrammaticScrollCoordinator::abortAnimations() {
+  m_queue.clear();
+}
+
+}  // namespace blink