Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 9e22bf067b59f01a58ce245bc9a14358d1735e64..54df566f3353ab7b02894efd3db3e7b5db11efa0 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -30,6 +30,7 @@
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/ScrollIntoViewOptionsOrBoolean.h"
 #include "bindings/core/v8/V8DOMActivityLogger.h"
 #include "core/CSSValueKeywords.h"
 #include "core/SVGNames.h"
@@ -94,6 +95,7 @@
 #include "core/frame/HostsUsingFeatures.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/ScrollIntoViewOptions.h"
 #include "core/frame/ScrollToOptions.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
@@ -141,6 +143,7 @@
 #include "platform/graphics/CompositorMutableProperties.h"
 #include "platform/graphics/CompositorMutation.h"
 #include "platform/scroll/ScrollableArea.h"
+#include "platform/scroll/SmoothScrollSequencer.h"
 #include "platform/wtf/BitVector.h"
 #include "platform/wtf/HashFunctions.h"
 #include "platform/wtf/text/CString.h"
@@ -430,7 +433,67 @@ AtomicString Element::LowercaseIfNecessary(const AtomicString& name) const {
                                                            : name;
 }
 
+void Element::scrollIntoView(ScrollIntoViewOptionsOrBoolean arg) {
+  ScrollIntoViewOptions options;
+  if (arg.isBoolean()) {
+    if (arg.getAsBoolean())
+      options.setBlock("start");
+    else
+      options.setBlock("end");
+    options.setInlinePosition("nearest");
+  } else if (arg.isScrollIntoViewOptions()) {
+    options = arg.getAsScrollIntoViewOptions();
+    if (!RuntimeEnabledFeatures::cssomSmoothScrollEnabled() &&
+        options.behavior() == "smooth") {
+      options.setBehavior("instant");
+    }
+  }
+  scrollIntoViewWithOptions(options);
+}
+
 void Element::scrollIntoView(bool align_to_top) {
+  ScrollIntoViewOptions options;
+  if (align_to_top)
+    options.setBlock("start");
+  else
+    options.setBlock("end");
+  options.setInlinePosition("nearest");
+  scrollIntoViewWithOptions(options);
+}
+
+static ScrollAlignment InputAlignmentToXYAlignment(
+    const ScrollIntoViewOptions& options,
+    bool is_x,
+    bool is_horizontal) {
+  String alignment = options.block();
+  if ((is_x && is_horizontal) || ((!is_x) && (!is_horizontal)))
+    alignment = options.inlinePosition();
+  if (alignment == "center")
+    return ScrollAlignment::kAlignCenterAlways;
+  if (alignment == "nearest")
+    return ScrollAlignment::kAlignToEdgeIfNeeded;
+  if (alignment == "start") {
+    return is_x ? ScrollAlignment::kAlignLeftAlways
+                : ScrollAlignment::kAlignTopAlways;
+  }
+  if (alignment == "end") {
+    return is_x ? ScrollAlignment::kAlignRightAlways
+                : ScrollAlignment::kAlignBottomAlways;
+  }
+
+  // Default values
+  if (is_horizontal) {
+    if (is_x)
+      return ScrollAlignment::kAlignToEdgeIfNeeded;
+    return ScrollAlignment::kAlignTopAlways;
+  }
+  // if (is_vertical)
+  if (is_x)
+    return ScrollAlignment::kAlignLeftAlways;
+  return ScrollAlignment::kAlignToEdgeIfNeeded;
+}
+
+void Element::scrollIntoViewWithOptions(const ScrollIntoViewOptions& options) {
   GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
 
   if (!GetLayoutObject())
@@ -439,18 +502,26 @@ void Element::scrollIntoView(bool align_to_top) {
   bool make_visible_in_visual_viewport =
       !GetDocument().GetPage()->GetSettings().GetInertVisualViewport();
 
+  ScrollBehavior behavior = kScrollBehaviorAuto;
+  if (options.behavior() == "smooth") {
+    behavior = kScrollBehaviorSmooth;
+  }
+
+  bool is_horizontal = GetComputedStyle()->IsHorizontalWritingMode();
+  ScrollAlignment align_x =
+      InputAlignmentToXYAlignment(options, true, is_horizontal);
+  ScrollAlignment align_y =
+      InputAlignmentToXYAlignment(options, false, is_horizontal);
+
+  if (GetDocument().GetPage())
+    GetDocument().GetPage()->GetSmoothScrollSequencer()->AbortAnimations();
   LayoutRect bounds = BoundingBox();
-  // Align to the top / bottom and to the closest edge.
-  if (align_to_top)
-    GetLayoutObject()->ScrollRectToVisible(
-        bounds, ScrollAlignment::kAlignToEdgeIfNeeded,
-        ScrollAlignment::kAlignTopAlways, kProgrammaticScroll,
-        make_visible_in_visual_viewport);
-  else
-    GetLayoutObject()->ScrollRectToVisible(
-        bounds, ScrollAlignment::kAlignToEdgeIfNeeded,
-        ScrollAlignment::kAlignBottomAlways, kProgrammaticScroll,
-        make_visible_in_visual_viewport);
+  GetLayoutObject()->ScrollRectToVisible(
+      bounds, align_x, align_y, kProgrammaticScroll,
+      make_visible_in_visual_viewport, behavior);
+
+  if (GetDocument().GetPage())
+    GetDocument().GetPage()->GetSmoothScrollSequencer()->RunQueuedAnimations();
 
   GetDocument().SetSequentialFocusNavigationStartingPoint(this);
 }