Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/page/Page.cpp

Index: third_party/WebKit/Source/core/page/Page.cpp
diff --git a/third_party/WebKit/Source/core/page/Page.cpp b/third_party/WebKit/Source/core/page/Page.cpp
index c8b68a9c243f97983cc37d7d4513b32538ef0494..d7dcd4add55bc6a953434110e30685aa14ee31d2 100644
--- a/third_party/WebKit/Source/core/page/Page.cpp
+++ b/third_party/WebKit/Source/core/page/Page.cpp
@@ -61,6 +61,7 @@
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/loader/fetch/ResourceFetcher.h"
 #include "platform/plugins/PluginData.h"
+#include "platform/scroll/SmoothScrollSequencer.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
@@ -164,6 +165,13 @@ ScrollingCoordinator* Page::scrollingCoordinator() {
   return m_scrollingCoordinator.get();
 }
 
+SmoothScrollSequencer* Page::smoothScrollSequencer() {
+  if (!m_smoothScrollSequencer)
+    m_smoothScrollSequencer = SmoothScrollSequencer::create();
+
+  return m_smoothScrollSequencer.get();
+}
+
 PageScaleConstraintsSet& Page::pageScaleConstraintsSet() {
   return *m_pageScaleConstraintsSet;
 }
@@ -617,6 +625,7 @@ DEFINE_TRACE(Page) {
   visitor->trace(m_contextMenuController);
   visitor->trace(m_pointerLockController);
   visitor->trace(m_scrollingCoordinator);
+  visitor->trace(m_smoothScrollSequencer);
   visitor->trace(m_browserControls);
   visitor->trace(m_consoleMessageStorage);
   visitor->trace(m_eventHandlerRegistry);