Revert of Compute snap offsets (both repeat and element based)

third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp

Index: third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
diff --git a/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp b/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
deleted file mode 100644
index 022f7a2a272cf758ab4af7fe93731a8109ff8664..0000000000000000000000000000000000000000
--- a/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
+++ /dev/null
@@ -1,171 +0,0 @@
-// Copyright 2016 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 "SnapCoordinator.h"
-
-#include "core/dom/Element.h"
-#include "core/dom/Node.h"
-#include "core/dom/NodeComputedStyle.h"
-#include "core/layout/LayoutBlock.h"
-#include "core/layout/LayoutBox.h"
-#include "core/layout/LayoutView.h"
-#include "core/style/ComputedStyle.h"
-#include "platform/LengthFunctions.h"
-
-namespace blink {
-
-SnapCoordinator::SnapCoordinator()
-    : m_snapContainers()
-{
-}
-
-SnapCoordinator::~SnapCoordinator() { }
-
-SnapCoordinator* SnapCoordinator::create()
-{
-    return new SnapCoordinator();
-}
-
-// Returns the scroll container that can be affected by this snap area.
-static LayoutBox* findSnapContainer(const LayoutBox& snapArea)
-{
-    // According to the new spec https://drafts.csswg.org/css-scroll-snap/#snap-model
-    // "Snap positions must only affect the nearest ancestor (on the element’s
-    // containing block chain) scroll container".
-    Element* viewportDefiningElement = snapArea.node()->document().viewportDefiningElement();
-    LayoutBox* box = snapArea.containingBlock();
-    while (box && !box->hasOverflowClip() && !box->isLayoutView() && box->node() != viewportDefiningElement)
-        box = box->containingBlock();
-
-    // If we reach to viewportDefiningElement then we dispatch to viewport
-    if (box->node() == viewportDefiningElement)
-        return snapArea.node()->document().layoutView();
-
-    return box;
-}
-
-void SnapCoordinator::snapAreaDidChange(LayoutBox& snapArea, const Vector<LengthPoint>& snapCoordinates)
-{
-    if (snapCoordinates.isEmpty()) {
-        snapArea.setSnapContainer(nullptr);
-        return;
-    }
-
-    if (LayoutBox* snapContainer = findSnapContainer(snapArea)) {
-        snapArea.setSnapContainer(snapContainer);
-    } else {
-        // TODO(majidvp): keep track of snap areas that do not have any
-        // container so that we check them again when a new container is
-        // added to the page.
-    }
-}
-
-void SnapCoordinator::snapContainerDidChange(LayoutBox& snapContainer, ScrollSnapType scrollSnapType)
-{
-    if (scrollSnapType == ScrollSnapTypeNone) {
-        // TODO(majidvp): Track and report these removals to CompositorWorker
-        // instance responsible for snapping
-        m_snapContainers.remove(&snapContainer);
-        snapContainer.clearSnapAreas();
-    } else {
-        m_snapContainers.add(&snapContainer);
-    }
-
-    // TODO(majidvp): Add logic to correctly handle orphaned snap areas here.
-    // 1. Removing container: find a new snap container for its orphan snap
-    // areas (most likely nearest ancestor of current container) otherwise add
-    // them to an orphan list.
-    // 2. Adding container: may take over snap areas from nearest ancestor snap
-    // container or from existing areas in orphan pool.
-}
-
-// Translate local snap coordinates into snap container's scrolling content
-// coordinate space.
-static Vector<FloatPoint> localToContainerSnapCoordinates(const LayoutBox& containerBox, const LayoutBox& snapArea)
-{
-    Vector<FloatPoint> result;
-    LayoutPoint scrollOffset(containerBox.scrollLeft(), containerBox.scrollTop());
-
-    const Vector<LengthPoint>& snapCoordinates = snapArea.style()->scrollSnapCoordinate();
-    for (auto& coordinate : snapCoordinates) {
-        FloatPoint localPoint = floatPointForLengthPoint(coordinate, FloatSize(snapArea.size()));
-        FloatPoint containerPoint = snapArea.localToAncestorPoint(localPoint, &containerBox);
-        containerPoint.moveBy(scrollOffset);
-        result.append(containerPoint);
-    }
-    return result;
-}
-
-Vector<double> SnapCoordinator::snapOffsets(const ContainerNode& element, ScrollbarOrientation orientation)
-{
-    const ComputedStyle* style = element.computedStyle();
-    const LayoutBox* snapContainer = element.layoutBox();
-    ASSERT(style);
-    ASSERT(snapContainer);
-
-    Vector<double> result;
-
-    if (style->getScrollSnapType() == ScrollSnapTypeNone)
-        return result;
-
-    const ScrollSnapPoints& snapPoints = (orientation == HorizontalScrollbar) ? style->scrollSnapPointsX() : style->scrollSnapPointsY();
-
-    LayoutUnit clientSize = (orientation == HorizontalScrollbar) ? snapContainer->clientWidth() : snapContainer->clientHeight();
-    LayoutUnit scrollSize = (orientation == HorizontalScrollbar) ? snapContainer->scrollWidth() : snapContainer->scrollHeight();
-
-    if (snapPoints.hasRepeat) {
-        LayoutUnit repeat = valueForLength(snapPoints.repeatOffset, clientSize);
-
-        // calc() values may be negative or zero in which case we clamp them to 1px.
-        // See: https://lists.w3.org/Archives/Public/www-style/2015Jul/0075.html
-        repeat = std::max<LayoutUnit>(repeat, LayoutUnit(1));
-        for (LayoutUnit offset = repeat; offset <= (scrollSize - clientSize); offset += repeat) {
-            result.append(offset.toFloat());
-        }
-    }
-
-    // Compute element-based snap points by mapping the snap coordinates from
-    // snap areas to snap container.
-    bool didAddSnapAreaOffset = false;
-    if (SnapAreaSet* snapAreas = snapContainer->snapAreas()) {
-        for (auto& snapArea : *snapAreas) {
-            Vector<FloatPoint> snapCoordinates = localToContainerSnapCoordinates(*snapContainer, *snapArea);
-            for (const FloatPoint& snapCoordinate : snapCoordinates) {
-                float snapOffset = (orientation == HorizontalScrollbar) ? snapCoordinate.x() : snapCoordinate.y();
-                if (snapOffset > scrollSize - clientSize)
-                    continue;
-                result.append(snapOffset);
-                didAddSnapAreaOffset = true;
-            }
-        }
-    }
-
-    if (didAddSnapAreaOffset)
-        std::sort(result.begin(), result.end());
-
-    return result;
-}
-
-#ifndef NDEBUG
-
-void SnapCoordinator::showSnapAreaMap()
-{
-    for (auto& container : m_snapContainers)
-        showSnapAreasFor(container);
-}
-
-void SnapCoordinator::showSnapAreasFor(const LayoutBox* container)
-{
-    const char* prefix = "    ";
-    container->node()->showNode();
-    if (SnapAreaSet* snapAreas = container->snapAreas()) {
-        for (auto& snapArea : *snapAreas) {
-            snapArea->node()->showNode(prefix);
-        }
-    }
-}
-
-#endif
-
-} // namespace blink