third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp - chromium/src.git - Git at Google

 // Copyright 2015 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 "core/layout/ScrollAnchor.h"

 #include "core/dom/ClientRect.h"
 #include "core/frame/VisualViewport.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/page/PrintContext.h"
 #include "core/paint/PaintLayerScrollableArea.h"
 #include "platform/testing/HistogramTester.h"
 #include "platform/testing/RuntimeEnabledFeaturesTestHelpers.h"

 namespace blink {

 using Corner = ScrollAnchor::Corner;

 typedef bool TestParamRootLayerScrolling;
 class ScrollAnchorTest
     : public testing::WithParamInterface<TestParamRootLayerScrolling>,
       private ScopedRootLayerScrollingForTest,
       public RenderingTest {
  public:
   ScrollAnchorTest() : ScopedRootLayerScrollingForTest(GetParam()) {
     RuntimeEnabledFeatures::SetScrollAnchoringEnabled(true);
   }
   ~ScrollAnchorTest() {
     RuntimeEnabledFeatures::SetScrollAnchoringEnabled(false);
   }

  protected:
   void Update() {
     // TODO(skobes): Use SimTest instead of RenderingTest and move into
     // Source/web?
     GetDocument().View()->UpdateAllLifecyclePhases();
   }

   ScrollableArea* LayoutViewport() {
     return GetDocument().View()->LayoutViewportScrollableArea();
   }

   VisualViewport& GetVisualViewport() {
     return GetDocument().View()->GetPage()->GetVisualViewport();
   }

   ScrollableArea* ScrollerForElement(Element* element) {
     return ToLayoutBox(element->GetLayoutObject())->GetScrollableArea();
   }

   ScrollAnchor& GetScrollAnchor(ScrollableArea* scroller) {
     DCHECK(scroller->IsLocalFrameView() ||
            scroller->IsPaintLayerScrollableArea());
     return *(scroller->GetScrollAnchor());
   }

   void SetHeight(Element* element, int height) {
     element->setAttribute(HTMLNames::styleAttr,
                           AtomicString(String::Format("height: %dpx", height)));
     Update();
   }

   void ScrollLayoutViewport(ScrollOffset delta) {
     Element* scrolling_element = GetDocument().scrollingElement();
     if (delta.Width())
       scrolling_element->setScrollLeft(scrolling_element->scrollLeft() +
                                        delta.Width());
     if (delta.Height())
       scrolling_element->setScrollTop(scrolling_element->scrollTop() +
                                       delta.Height());
   }
 };

 INSTANTIATE_TEST_CASE_P(All, ScrollAnchorTest, ::testing::Bool());

 // TODO(ymalik): Currently, this should be the first test in the file to avoid
 // failure when running with other tests. Dig into this more and fix.
 TEST_P(ScrollAnchorTest, UMAMetricUpdated) {
   HistogramTester histogram_tester;
   SetBodyInnerHTML(
       "<style> body { height: 1000px } div { height: 100px } </style>"
       "<div id='block1'>abc</div>"
       "<div id='block2'>def</div>");

   ScrollableArea* viewport = LayoutViewport();

   // Scroll position not adjusted, metric not updated.
   ScrollLayoutViewport(ScrollOffset(0, 150));
   histogram_tester.ExpectTotalCount("Layout.ScrollAnchor.AdjustedScrollOffset",
                                     0);

   // Height changed, verify metric updated once.
   SetHeight(GetDocument().getElementById("block1"), 200);
   histogram_tester.ExpectUniqueSample(
       "Layout.ScrollAnchor.AdjustedScrollOffset", 1, 1);

   EXPECT_EQ(250, viewport->ScrollOffsetInt().Height());
   EXPECT_EQ(GetDocument().getElementById("block2")->GetLayoutObject(),
             GetScrollAnchor(viewport).AnchorObject());
 }

 // TODO(skobes): Convert this to web-platform-tests when visual viewport API is
 // launched (http://crbug.com/635031).
 TEST_P(ScrollAnchorTest, VisualViewportAnchors) {
   SetBodyInnerHTML(
       "<style>"
       "    * { font-size: 1.2em; font-family: sans-serif; }"
       "    div { height: 100px; width: 20px; background-color: pink; }"
       "</style>"
       "<div id='div'></div>"
       "<div id='text'><b>This is a scroll anchoring test</div>");

   ScrollableArea* l_viewport = LayoutViewport();
   VisualViewport& v_viewport = GetVisualViewport();

   v_viewport.SetScale(2.0);

   // No anchor at origin (0,0).
   EXPECT_EQ(nullptr, GetScrollAnchor(l_viewport).AnchorObject());

   // Scroll the visual viewport to bring #text to the top.
   int top =
       GetDocument().getElementById("text")->getBoundingClientRect()->top();
   v_viewport.SetLocation(FloatPoint(0, top));

   SetHeight(GetDocument().getElementById("div"), 10);
   EXPECT_EQ(GetDocument().getElementById("text")->GetLayoutObject(),
             GetScrollAnchor(l_viewport).AnchorObject());
   EXPECT_EQ(top - 90, v_viewport.ScrollOffsetInt().Height());

   SetHeight(GetDocument().getElementById("div"), 100);
   EXPECT_EQ(GetDocument().getElementById("text")->GetLayoutObject(),
             GetScrollAnchor(l_viewport).AnchorObject());
   EXPECT_EQ(top, v_viewport.ScrollOffsetInt().Height());

   // Scrolling the visual viewport should clear the anchor.
   v_viewport.SetLocation(FloatPoint(0, 0));
   EXPECT_EQ(nullptr, GetScrollAnchor(l_viewport).AnchorObject());
 }

 // Test that a non-anchoring scroll on scroller clears scroll anchors for all
 // parent scrollers.
 TEST_P(ScrollAnchorTest, ClearScrollAnchorsOnAncestors) {
   SetBodyInnerHTML(
       "<style>"
       "    body { height: 1000px } div { height: 200px }"
       "    #scroller { height: 100px; width: 200px; overflow: scroll; }"
       "</style>"
       "<div id='changer'>abc</div>"
       "<div id='anchor'>def</div>"
       "<div id='scroller'><div></div></div>");

   ScrollableArea* viewport = LayoutViewport();

   ScrollLayoutViewport(ScrollOffset(0, 250));
   SetHeight(GetDocument().getElementById("changer"), 300);

   EXPECT_EQ(350, viewport->ScrollOffsetInt().Height());
   EXPECT_EQ(GetDocument().getElementById("anchor")->GetLayoutObject(),
             GetScrollAnchor(viewport).AnchorObject());

   // Scrolling the nested scroller should clear the anchor on the main frame.
   ScrollableArea* scroller =
       ScrollerForElement(GetDocument().getElementById("scroller"));
   scroller->ScrollBy(ScrollOffset(0, 100), kUserScroll);
   EXPECT_EQ(nullptr, GetScrollAnchor(viewport).AnchorObject());
 }

 TEST_P(ScrollAnchorTest, AncestorClearingWithSiblingReference) {
   SetBodyInnerHTML(
       "<style>"
       ".scroller {"
       "  overflow: scroll;"
       "  width: 400px;"
       "  height: 400px;"
       "}"
       ".space {"
       "  width: 100px;"
       "  height: 600px;"
       "}"
       "</style>"
       "<div id='s1' class='scroller'>"
       "  <div id='anchor' class='space'></div>"
       "</div>"
       "<div id='s2' class='scroller'>"
       "  <div class='space'></div>"
       "</div>");
   Element* s1 = GetDocument().getElementById("s1");
   Element* s2 = GetDocument().getElementById("s2");
   Element* anchor = GetDocument().getElementById("anchor");

   // Set non-zero scroll offsets for #s1 and #document
   s1->setScrollTop(100);
   ScrollLayoutViewport(ScrollOffset(0, 100));

   // Invalidate layout.
   SetHeight(anchor, 500);

   // This forces layout, during which both #s1 and #document will anchor to
   // #anchor. Then the scroll clears #s2 and #document.  Since #anchor is still
   // referenced by #s1, its IsScrollAnchorObject bit must remain set.
   s2->setScrollTop(100);

   // This should clear #s1.  If #anchor had its bit cleared already we would
   // crash in update().
   s1->RemoveChild(anchor);
   Update();
 }

 TEST_P(ScrollAnchorTest, FractionalOffsetsAreRoundedBeforeComparing) {
   SetBodyInnerHTML(
       "<style> body { height: 1000px } </style>"
       "<div id='block1' style='height: 50.4px'>abc</div>"
       "<div id='block2' style='height: 100px'>def</div>");

   ScrollableArea* viewport = LayoutViewport();
   ScrollLayoutViewport(ScrollOffset(0, 100));

   GetDocument().getElementById("block1")->setAttribute(HTMLNames::styleAttr,
                                                        "height: 50.6px");
   Update();

   EXPECT_EQ(101, viewport->ScrollOffsetInt().Height());
 }

 TEST_P(ScrollAnchorTest, AvoidStickyAnchorWhichMovesWithScroll) {
   SetBodyInnerHTML(
       "<style> body { height: 1000px } </style>"
       "<div id='block1' style='height: 50px'>abc</div>"
       "<div id='block2' style='height: 100px; position: sticky; top: 0;'>"
       "    def</div>");

   ScrollableArea* viewport = LayoutViewport();
   ScrollLayoutViewport(ScrollOffset(0, 60));

   GetDocument().getElementById("block1")->setAttribute(HTMLNames::styleAttr,
                                                        "height: 100px");
   Update();

   EXPECT_EQ(60, viewport->ScrollOffsetInt().Height());
 }

 TEST_P(ScrollAnchorTest, AnchorWithLayerInScrollingDiv) {
   SetBodyInnerHTML(
       "<style>"
       "    #scroller { overflow: scroll; width: 500px; height: 400px; }"
       "    div { height: 100px }"
       "    #block2 { overflow: hidden }"
       "    #space { height: 1000px; }"
       "</style>"
       "<div id='scroller'><div id='space'>"
       "<div id='block1'>abc</div>"
       "<div id='block2'>def</div>"
       "</div></div>");

   ScrollableArea* scroller =
       ScrollerForElement(GetDocument().getElementById("scroller"));
   Element* block1 = GetDocument().getElementById("block1");
   Element* block2 = GetDocument().getElementById("block2");

   scroller->ScrollBy(ScrollOffset(0, 150), kUserScroll);

   // In this layout pass we will anchor to #block2 which has its own PaintLayer.
   SetHeight(block1, 200);
   EXPECT_EQ(250, scroller->ScrollOffsetInt().Height());
   EXPECT_EQ(block2->GetLayoutObject(),
             GetScrollAnchor(scroller).AnchorObject());

   // Test that the anchor object can be destroyed without affecting the scroll
   // position.
   block2->remove();
   Update();
   EXPECT_EQ(250, scroller->ScrollOffsetInt().Height());
 }

 // Verify that a nested scroller with a div that has its own PaintLayer can be
 // removed without causing a crash. This test passes if it doesn't crash.
 TEST_P(ScrollAnchorTest, RemoveScrollerWithLayerInScrollingDiv) {
   SetBodyInnerHTML(
       "<style>"
       "    body { height: 2000px }"
       "    #scroller { overflow: scroll; width: 500px; height: 400px}"
       "    #block1 { height: 100px; width: 100px; overflow: hidden}"
       "    #anchor { height: 1000px; }"
       "</style>"
       "<div id='changer1'></div>"
       "<div id='scroller'>"
       "  <div id='changer2'></div>"
       "  <div id='block1'></div>"
       "  <div id='anchor'></div>"
       "</div>");

   ScrollableArea* viewport = LayoutViewport();
   ScrollableArea* scroller =
       ScrollerForElement(GetDocument().getElementById("scroller"));
   Element* changer1 = GetDocument().getElementById("changer1");
   Element* changer2 = GetDocument().getElementById("changer2");
   Element* anchor = GetDocument().getElementById("anchor");

   scroller->ScrollBy(ScrollOffset(0, 150), kUserScroll);
   ScrollLayoutViewport(ScrollOffset(0, 50));

   // In this layout pass both the inner and outer scroller will anchor to
   // #anchor.
   SetHeight(changer1, 100);
   SetHeight(changer2, 100);
   EXPECT_EQ(250, scroller->ScrollOffsetInt().Height());
   EXPECT_EQ(anchor->GetLayoutObject(),
             GetScrollAnchor(scroller).AnchorObject());
   EXPECT_EQ(anchor->GetLayoutObject(),
             GetScrollAnchor(viewport).AnchorObject());

   // Test that the inner scroller can be destroyed without crashing.
   GetDocument().getElementById("scroller")->remove();
   Update();
 }

 TEST_P(ScrollAnchorTest, FlexboxDelayedClampingAlsoDelaysAdjustment) {
   SetBodyInnerHTML(
       "<style>"
       "    html { overflow: hidden; }"
       "    body {"
       "        position: absolute; display: flex;"
       "        top: 0; bottom: 0; margin: 0;"
       "    }"
       "    #scroller { overflow: auto; }"
       "    #spacer { width: 600px; height: 1200px; }"
       "    #before { height: 50px; }"
       "    #anchor {"
       "        width: 100px; height: 100px;"
       "        background-color: #8f8;"
       "    }"
       "</style>"
       "<div id='scroller'>"
       "    <div id='spacer'>"
       "        <div id='before'></div>"
       "        <div id='anchor'></div>"
       "    </div>"
       "</div>");

   Element* scroller = GetDocument().getElementById("scroller");
   scroller->setScrollTop(100);

   SetHeight(GetDocument().getElementById("before"), 100);
   EXPECT_EQ(150, ScrollerForElement(scroller)->ScrollOffsetInt().Height());
 }

 TEST_P(ScrollAnchorTest, FlexboxDelayedAdjustmentRespectsSANACLAP) {
   SetBodyInnerHTML(
       "<style>"
       "    html { overflow: hidden; }"
       "    body {"
       "        position: absolute; display: flex;"
       "        top: 0; bottom: 0; margin: 0;"
       "    }"
       "    #scroller { overflow: auto; }"
       "    #spacer { width: 600px; height: 1200px; }"
       "    #anchor {"
       "        position: relative; top: 50px;"
       "        width: 100px; height: 100px;"
       "        background-color: #8f8;"
       "    }"
       "</style>"
       "<div id='scroller'>"
       "    <div id='spacer'>"
       "        <div id='anchor'></div>"
       "    </div>"
       "</div>");

   Element* scroller = GetDocument().getElementById("scroller");
   scroller->setScrollTop(100);

   GetDocument().getElementById("spacer")->setAttribute(HTMLNames::styleAttr,
                                                        "margin-top: 50px");
   Update();
   EXPECT_EQ(100, ScrollerForElement(scroller)->ScrollOffsetInt().Height());
 }

 // TODO(skobes): Convert this to web-platform-tests when document.rootScroller
 // is launched (http://crbug.com/505516).
 TEST_P(ScrollAnchorTest, NonDefaultRootScroller) {
   SetBodyInnerHTML(
       "<style>"
       "    ::-webkit-scrollbar {"
       "      width: 0px; height: 0px;"
       "    }"
       "    body, html {"
       "      margin: 0px; width: 100%; height: 100%;"
       "    }"
       "    #rootscroller {"
       "      overflow: scroll; width: 100%; height: 100%;"
       "    }"
       "    .spacer {"
       "      height: 600px; width: 100px;"
       "    }"
       "    #target {"
       "      height: 100px; width: 100px; background-color: red;"
       "    }"
       "</style>"
       "<div id='rootscroller'>"
       "    <div id='firstChild' class='spacer'></div>"
       "    <div id='target'></div>"
       "    <div class='spacer'></div>"
       "</div>"
       "<div class='spacer'></div>");

   Element* root_scroller_element = GetDocument().getElementById("rootscroller");

   NonThrowableExceptionState non_throw;
   GetDocument().setRootScroller(root_scroller_element, non_throw);
   GetDocument().View()->UpdateAllLifecyclePhases();

   ScrollableArea* scroller = ScrollerForElement(root_scroller_element);

   // By making the #rootScroller DIV the rootScroller, it should become the
   // layout viewport on the RootFrameViewport.
   ASSERT_EQ(scroller,
             &GetDocument().View()->GetRootFrameViewport()->LayoutViewport());

   // The #rootScroller DIV's anchor should have the RootFrameViewport set as
   // the scroller, rather than the FrameView's anchor.

   root_scroller_element->setScrollTop(600);

   SetHeight(GetDocument().getElementById("firstChild"), 1000);

   // Scroll anchoring should be applied to #rootScroller.
   EXPECT_EQ(1000, scroller->GetScrollOffset().Height());
   EXPECT_EQ(GetDocument().getElementById("target")->GetLayoutObject(),
             GetScrollAnchor(scroller).AnchorObject());
   // Scroll anchoring should not apply within main frame.
   EXPECT_EQ(0, LayoutViewport()->GetScrollOffset().Height());
   EXPECT_EQ(nullptr, GetScrollAnchor(LayoutViewport()).AnchorObject());
 }

 // This test verifies that scroll anchoring is disabled when the document is in
 // printing mode.
 TEST_P(ScrollAnchorTest, AnchoringDisabledForPrinting) {
   SetBodyInnerHTML(
       "<style> body { height: 1000px } div { height: 100px } </style>"
       "<div id='block1'>abc</div>"
       "<div id='block2'>def</div>");

   ScrollableArea* viewport = LayoutViewport();
   ScrollLayoutViewport(ScrollOffset(0, 150));

   // This will trigger printing and layout.
   PrintContext::NumberOfPages(GetDocument().GetFrame(), FloatSize(500, 500));

   EXPECT_EQ(150, viewport->ScrollOffsetInt().Height());
   EXPECT_EQ(nullptr, GetScrollAnchor(viewport).AnchorObject());
 }

 }
	// Copyright 2015 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 "core/layout/ScrollAnchor.h"

	#include "core/dom/ClientRect.h"
	#include "core/frame/VisualViewport.h"
	#include "core/layout/LayoutBox.h"
	#include "core/layout/LayoutTestHelper.h"
	#include "core/page/PrintContext.h"
	#include "core/paint/PaintLayerScrollableArea.h"
	#include "platform/testing/HistogramTester.h"
	#include "platform/testing/RuntimeEnabledFeaturesTestHelpers.h"

	namespace blink {

	using Corner = ScrollAnchor::Corner;

	typedef bool TestParamRootLayerScrolling;
	class ScrollAnchorTest
	: public testing::WithParamInterface<TestParamRootLayerScrolling>,
	private ScopedRootLayerScrollingForTest,
	public RenderingTest {
	public:
	ScrollAnchorTest() : ScopedRootLayerScrollingForTest(GetParam()) {
	RuntimeEnabledFeatures::SetScrollAnchoringEnabled(true);
	}
	~ScrollAnchorTest() {
	RuntimeEnabledFeatures::SetScrollAnchoringEnabled(false);
	}

	protected:
	void Update() {
	// TODO(skobes): Use SimTest instead of RenderingTest and move into
	// Source/web?
	GetDocument().View()->UpdateAllLifecyclePhases();
	}

	ScrollableArea* LayoutViewport() {
	return GetDocument().View()->LayoutViewportScrollableArea();
	}

	VisualViewport& GetVisualViewport() {
	return GetDocument().View()->GetPage()->GetVisualViewport();
	}

	ScrollableArea* ScrollerForElement(Element* element) {
	return ToLayoutBox(element->GetLayoutObject())->GetScrollableArea();
	}

	ScrollAnchor& GetScrollAnchor(ScrollableArea* scroller) {
	DCHECK(scroller->IsLocalFrameView() \|\|
	scroller->IsPaintLayerScrollableArea());
	return *(scroller->GetScrollAnchor());
	}

	void SetHeight(Element* element, int height) {
	element->setAttribute(HTMLNames::styleAttr,
	AtomicString(String::Format("height: %dpx", height)));
	Update();
	}

	void ScrollLayoutViewport(ScrollOffset delta) {
	Element* scrolling_element = GetDocument().scrollingElement();
	if (delta.Width())
	scrolling_element->setScrollLeft(scrolling_element->scrollLeft() +
	delta.Width());
	if (delta.Height())
	scrolling_element->setScrollTop(scrolling_element->scrollTop() +
	delta.Height());
	}
	};

	INSTANTIATE_TEST_CASE_P(All, ScrollAnchorTest, ::testing::Bool());

	// TODO(ymalik): Currently, this should be the first test in the file to avoid
	// failure when running with other tests. Dig into this more and fix.
	TEST_P(ScrollAnchorTest, UMAMetricUpdated) {
	HistogramTester histogram_tester;
	SetBodyInnerHTML(
	"<style> body { height: 1000px } div { height: 100px } </style>"
	"<div id='block1'>abc</div>"
	"<div id='block2'>def</div>");

	ScrollableArea* viewport = LayoutViewport();

	// Scroll position not adjusted, metric not updated.
	ScrollLayoutViewport(ScrollOffset(0, 150));
	histogram_tester.ExpectTotalCount("Layout.ScrollAnchor.AdjustedScrollOffset",
	0);

	// Height changed, verify metric updated once.
	SetHeight(GetDocument().getElementById("block1"), 200);
	histogram_tester.ExpectUniqueSample(
	"Layout.ScrollAnchor.AdjustedScrollOffset", 1, 1);

	EXPECT_EQ(250, viewport->ScrollOffsetInt().Height());
	EXPECT_EQ(GetDocument().getElementById("block2")->GetLayoutObject(),
	GetScrollAnchor(viewport).AnchorObject());
	}

	// TODO(skobes): Convert this to web-platform-tests when visual viewport API is
	// launched (http://crbug.com/635031).
	TEST_P(ScrollAnchorTest, VisualViewportAnchors) {
	SetBodyInnerHTML(
	"<style>"
	" * { font-size: 1.2em; font-family: sans-serif; }"
	" div { height: 100px; width: 20px; background-color: pink; }"
	"</style>"
	"<div id='div'></div>"
	"<div id='text'><b>This is a scroll anchoring test</div>");

	ScrollableArea* l_viewport = LayoutViewport();
	VisualViewport& v_viewport = GetVisualViewport();

	v_viewport.SetScale(2.0);

	// No anchor at origin (0,0).
	EXPECT_EQ(nullptr, GetScrollAnchor(l_viewport).AnchorObject());

	// Scroll the visual viewport to bring #text to the top.
	int top =
	GetDocument().getElementById("text")->getBoundingClientRect()->top();
	v_viewport.SetLocation(FloatPoint(0, top));

	SetHeight(GetDocument().getElementById("div"), 10);
	EXPECT_EQ(GetDocument().getElementById("text")->GetLayoutObject(),
	GetScrollAnchor(l_viewport).AnchorObject());
	EXPECT_EQ(top - 90, v_viewport.ScrollOffsetInt().Height());

	SetHeight(GetDocument().getElementById("div"), 100);
	EXPECT_EQ(GetDocument().getElementById("text")->GetLayoutObject(),
	GetScrollAnchor(l_viewport).AnchorObject());
	EXPECT_EQ(top, v_viewport.ScrollOffsetInt().Height());

	// Scrolling the visual viewport should clear the anchor.
	v_viewport.SetLocation(FloatPoint(0, 0));
	EXPECT_EQ(nullptr, GetScrollAnchor(l_viewport).AnchorObject());
	}

	// Test that a non-anchoring scroll on scroller clears scroll anchors for all
	// parent scrollers.
	TEST_P(ScrollAnchorTest, ClearScrollAnchorsOnAncestors) {
	SetBodyInnerHTML(
	"<style>"
	" body { height: 1000px } div { height: 200px }"
	" #scroller { height: 100px; width: 200px; overflow: scroll; }"
	"</style>"
	"<div id='changer'>abc</div>"
	"<div id='anchor'>def</div>"
	"<div id='scroller'><div></div></div>");

	ScrollableArea* viewport = LayoutViewport();

	ScrollLayoutViewport(ScrollOffset(0, 250));
	SetHeight(GetDocument().getElementById("changer"), 300);

	EXPECT_EQ(350, viewport->ScrollOffsetInt().Height());
	EXPECT_EQ(GetDocument().getElementById("anchor")->GetLayoutObject(),
	GetScrollAnchor(viewport).AnchorObject());

	// Scrolling the nested scroller should clear the anchor on the main frame.
	ScrollableArea* scroller =
	ScrollerForElement(GetDocument().getElementById("scroller"));
	scroller->ScrollBy(ScrollOffset(0, 100), kUserScroll);
	EXPECT_EQ(nullptr, GetScrollAnchor(viewport).AnchorObject());
	}

	TEST_P(ScrollAnchorTest, AncestorClearingWithSiblingReference) {
	SetBodyInnerHTML(
	"<style>"
	".scroller {"
	" overflow: scroll;"
	" width: 400px;"
	" height: 400px;"
	"}"
	".space {"
	" width: 100px;"
	" height: 600px;"
	"}"
	"</style>"
	"<div id='s1' class='scroller'>"
	" <div id='anchor' class='space'></div>"
	"</div>"
	"<div id='s2' class='scroller'>"
	" <div class='space'></div>"
	"</div>");
	Element* s1 = GetDocument().getElementById("s1");
	Element* s2 = GetDocument().getElementById("s2");
	Element* anchor = GetDocument().getElementById("anchor");

	// Set non-zero scroll offsets for #s1 and #document
	s1->setScrollTop(100);
	ScrollLayoutViewport(ScrollOffset(0, 100));

	// Invalidate layout.
	SetHeight(anchor, 500);

	// This forces layout, during which both #s1 and #document will anchor to
	// #anchor. Then the scroll clears #s2 and #document. Since #anchor is still
	// referenced by #s1, its IsScrollAnchorObject bit must remain set.
	s2->setScrollTop(100);

	// This should clear #s1. If #anchor had its bit cleared already we would
	// crash in update().
	s1->RemoveChild(anchor);
	Update();
	}

	TEST_P(ScrollAnchorTest, FractionalOffsetsAreRoundedBeforeComparing) {
	SetBodyInnerHTML(
	"<style> body { height: 1000px } </style>"
	"<div id='block1' style='height: 50.4px'>abc</div>"
	"<div id='block2' style='height: 100px'>def</div>");

	ScrollableArea* viewport = LayoutViewport();
	ScrollLayoutViewport(ScrollOffset(0, 100));

	GetDocument().getElementById("block1")->setAttribute(HTMLNames::styleAttr,
	"height: 50.6px");
	Update();

	EXPECT_EQ(101, viewport->ScrollOffsetInt().Height());
	}

	TEST_P(ScrollAnchorTest, AvoidStickyAnchorWhichMovesWithScroll) {
	SetBodyInnerHTML(
	"<style> body { height: 1000px } </style>"
	"<div id='block1' style='height: 50px'>abc</div>"
	"<div id='block2' style='height: 100px; position: sticky; top: 0;'>"
	" def</div>");

	ScrollableArea* viewport = LayoutViewport();
	ScrollLayoutViewport(ScrollOffset(0, 60));

	GetDocument().getElementById("block1")->setAttribute(HTMLNames::styleAttr,
	"height: 100px");
	Update();

	EXPECT_EQ(60, viewport->ScrollOffsetInt().Height());
	}

	TEST_P(ScrollAnchorTest, AnchorWithLayerInScrollingDiv) {
	SetBodyInnerHTML(
	"<style>"
	" #scroller { overflow: scroll; width: 500px; height: 400px; }"
	" div { height: 100px }"
	" #block2 { overflow: hidden }"
	" #space { height: 1000px; }"
	"</style>"
	"<div id='scroller'><div id='space'>"
	"<div id='block1'>abc</div>"
	"<div id='block2'>def</div>"
	"</div></div>");

	ScrollableArea* scroller =
	ScrollerForElement(GetDocument().getElementById("scroller"));
	Element* block1 = GetDocument().getElementById("block1");
	Element* block2 = GetDocument().getElementById("block2");

	scroller->ScrollBy(ScrollOffset(0, 150), kUserScroll);

	// In this layout pass we will anchor to #block2 which has its own PaintLayer.
	SetHeight(block1, 200);
	EXPECT_EQ(250, scroller->ScrollOffsetInt().Height());
	EXPECT_EQ(block2->GetLayoutObject(),
	GetScrollAnchor(scroller).AnchorObject());

	// Test that the anchor object can be destroyed without affecting the scroll
	// position.
	block2->remove();
	Update();
	EXPECT_EQ(250, scroller->ScrollOffsetInt().Height());
	}

	// Verify that a nested scroller with a div that has its own PaintLayer can be
	// removed without causing a crash. This test passes if it doesn't crash.
	TEST_P(ScrollAnchorTest, RemoveScrollerWithLayerInScrollingDiv) {
	SetBodyInnerHTML(
	"<style>"
	" body { height: 2000px }"
	" #scroller { overflow: scroll; width: 500px; height: 400px}"
	" #block1 { height: 100px; width: 100px; overflow: hidden}"
	" #anchor { height: 1000px; }"
	"</style>"
	"<div id='changer1'></div>"
	"<div id='scroller'>"
	" <div id='changer2'></div>"
	" <div id='block1'></div>"
	" <div id='anchor'></div>"
	"</div>");

	ScrollableArea* viewport = LayoutViewport();
	ScrollableArea* scroller =
	ScrollerForElement(GetDocument().getElementById("scroller"));
	Element* changer1 = GetDocument().getElementById("changer1");
	Element* changer2 = GetDocument().getElementById("changer2");
	Element* anchor = GetDocument().getElementById("anchor");

	scroller->ScrollBy(ScrollOffset(0, 150), kUserScroll);
	ScrollLayoutViewport(ScrollOffset(0, 50));

	// In this layout pass both the inner and outer scroller will anchor to
	// #anchor.
	SetHeight(changer1, 100);
	SetHeight(changer2, 100);
	EXPECT_EQ(250, scroller->ScrollOffsetInt().Height());
	EXPECT_EQ(anchor->GetLayoutObject(),
	GetScrollAnchor(scroller).AnchorObject());
	EXPECT_EQ(anchor->GetLayoutObject(),
	GetScrollAnchor(viewport).AnchorObject());

	// Test that the inner scroller can be destroyed without crashing.
	GetDocument().getElementById("scroller")->remove();
	Update();
	}

	TEST_P(ScrollAnchorTest, FlexboxDelayedClampingAlsoDelaysAdjustment) {
	SetBodyInnerHTML(
	"<style>"
	" html { overflow: hidden; }"
	" body {"
	" position: absolute; display: flex;"
	" top: 0; bottom: 0; margin: 0;"
	" }"
	" #scroller { overflow: auto; }"
	" #spacer { width: 600px; height: 1200px; }"
	" #before { height: 50px; }"
	" #anchor {"
	" width: 100px; height: 100px;"
	" background-color: #8f8;"
	" }"
	"</style>"
	"<div id='scroller'>"
	" <div id='spacer'>"
	" <div id='before'></div>"
	" <div id='anchor'></div>"
	" </div>"
	"</div>");

	Element* scroller = GetDocument().getElementById("scroller");
	scroller->setScrollTop(100);

	SetHeight(GetDocument().getElementById("before"), 100);
	EXPECT_EQ(150, ScrollerForElement(scroller)->ScrollOffsetInt().Height());
	}

	TEST_P(ScrollAnchorTest, FlexboxDelayedAdjustmentRespectsSANACLAP) {
	SetBodyInnerHTML(
	"<style>"
	" html { overflow: hidden; }"
	" body {"
	" position: absolute; display: flex;"
	" top: 0; bottom: 0; margin: 0;"
	" }"
	" #scroller { overflow: auto; }"
	" #spacer { width: 600px; height: 1200px; }"
	" #anchor {"
	" position: relative; top: 50px;"
	" width: 100px; height: 100px;"
	" background-color: #8f8;"
	" }"
	"</style>"
	"<div id='scroller'>"
	" <div id='spacer'>"
	" <div id='anchor'></div>"
	" </div>"
	"</div>");

	Element* scroller = GetDocument().getElementById("scroller");
	scroller->setScrollTop(100);

	GetDocument().getElementById("spacer")->setAttribute(HTMLNames::styleAttr,
	"margin-top: 50px");
	Update();
	EXPECT_EQ(100, ScrollerForElement(scroller)->ScrollOffsetInt().Height());
	}

	// TODO(skobes): Convert this to web-platform-tests when document.rootScroller
	// is launched (http://crbug.com/505516).
	TEST_P(ScrollAnchorTest, NonDefaultRootScroller) {
	SetBodyInnerHTML(
	"<style>"
	" ::-webkit-scrollbar {"
	" width: 0px; height: 0px;"
	" }"
	" body, html {"
	" margin: 0px; width: 100%; height: 100%;"
	" }"
	" #rootscroller {"
	" overflow: scroll; width: 100%; height: 100%;"
	" }"
	" .spacer {"
	" height: 600px; width: 100px;"
	" }"
	" #target {"
	" height: 100px; width: 100px; background-color: red;"
	" }"
	"</style>"
	"<div id='rootscroller'>"
	" <div id='firstChild' class='spacer'></div>"
	" <div id='target'></div>"
	" <div class='spacer'></div>"
	"</div>"
	"<div class='spacer'></div>");

	Element* root_scroller_element = GetDocument().getElementById("rootscroller");

	NonThrowableExceptionState non_throw;
	GetDocument().setRootScroller(root_scroller_element, non_throw);
	GetDocument().View()->UpdateAllLifecyclePhases();

	ScrollableArea* scroller = ScrollerForElement(root_scroller_element);

	// By making the #rootScroller DIV the rootScroller, it should become the
	// layout viewport on the RootFrameViewport.
	ASSERT_EQ(scroller,
	&GetDocument().View()->GetRootFrameViewport()->LayoutViewport());

	// The #rootScroller DIV's anchor should have the RootFrameViewport set as
	// the scroller, rather than the FrameView's anchor.

	root_scroller_element->setScrollTop(600);

	SetHeight(GetDocument().getElementById("firstChild"), 1000);

	// Scroll anchoring should be applied to #rootScroller.
	EXPECT_EQ(1000, scroller->GetScrollOffset().Height());
	EXPECT_EQ(GetDocument().getElementById("target")->GetLayoutObject(),
	GetScrollAnchor(scroller).AnchorObject());
	// Scroll anchoring should not apply within main frame.
	EXPECT_EQ(0, LayoutViewport()->GetScrollOffset().Height());
	EXPECT_EQ(nullptr, GetScrollAnchor(LayoutViewport()).AnchorObject());
	}

	// This test verifies that scroll anchoring is disabled when the document is in
	// printing mode.
	TEST_P(ScrollAnchorTest, AnchoringDisabledForPrinting) {
	SetBodyInnerHTML(
	"<style> body { height: 1000px } div { height: 100px } </style>"
	"<div id='block1'>abc</div>"
	"<div id='block2'>def</div>");

	ScrollableArea* viewport = LayoutViewport();
	ScrollLayoutViewport(ScrollOffset(0, 150));

	// This will trigger printing and layout.
	PrintContext::NumberOfPages(GetDocument().GetFrame(), FloatSize(500, 500));

	EXPECT_EQ(150, viewport->ScrollOffsetInt().Height());
	EXPECT_EQ(nullptr, GetScrollAnchor(viewport).AnchorObject());
	}

	}