Clear scroll anchor on all parent scrollers from ScrollAnchor::clear

third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp

Index: third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp
diff --git a/third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp b/third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp
index 214c5e57195ff36402510100de76d59a25a30f5c..33ddb634351724282f9ff075870de4b510b574e8 100644
--- a/third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp
+++ b/third_party/WebKit/Source/core/layout/ScrollAnchorTest.cpp
@@ -17,7 +17,8 @@ using Corner = ScrollAnchor::Corner;
 
 class ScrollAnchorTest : public RenderingTest {
  public:
-  ScrollAnchorTest() {
+  explicit ScrollAnchorTest(FrameLoaderClient* frameLoaderClient = nullptr)
+      : RenderingTest(frameLoaderClient) {
     RuntimeEnabledFeatures::setScrollAnchoringEnabled(true);
   }
   ~ScrollAnchorTest() {
@@ -64,6 +65,12 @@ class ScrollAnchorTest : public RenderingTest {
   }
 };
 
+class ScrollAnchorFrameTest : public ScrollAnchorTest {
+ public:
+  ScrollAnchorFrameTest()
+      : ScrollAnchorTest(SingleChildFrameLoaderClient::create()) {}
+};
+
 // 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_F(ScrollAnchorTest, UMAMetricUpdated) {
@@ -240,6 +247,63 @@ TEST_F(ScrollAnchorTest, AnchoringWhenContentRemovedFromScrollingDiv) {
             scrollAnchor(scroller).anchorObject());
 }
 
+// Test that a non-anchoring scroll on scroller clears scroll anchors for all
+// parent scrollers.
+TEST_F(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(DoubleSize(0, 250));
+  setHeight(document().getElementById("changer"), 300);
+
+  EXPECT_EQ(350, viewport->scrollPosition().y());
+  EXPECT_EQ(document().getElementById("anchor")->layoutObject(),
+            scrollAnchor(viewport).anchorObject());
+
+  // Scrolling the nested scroller should clear the anchor on the main frame.
+  ScrollableArea* scroller =
+      scrollerForElement(document().getElementById("scroller"));
+  scroller->scrollBy(DoubleSize(0, 100), UserScroll);
+  EXPECT_EQ(nullptr, scrollAnchor(viewport).anchorObject());
+}
+
+TEST_F(ScrollAnchorFrameTest, ClearScrollAnchorsOnAncestorsOfIframe) {
+  document().setBaseURLOverride(KURL(ParsedURLString, "http://test.com"));
+  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>"
+      "<iframe id='scroller' src='http://test.com'></iframe>");
+
+  Document& frameDocument =
+      setupChildIframe("scroller", "<style> body { height: 1000px } </style>");
+
+  ScrollableArea* viewport = layoutViewport();
+
+  scrollLayoutViewport(DoubleSize(0, 250));
+  setHeight(document().getElementById("changer"), 300);
+
+  EXPECT_EQ(350, viewport->scrollPosition().y());
+  EXPECT_EQ(document().getElementById("anchor")->layoutObject(),
+            scrollAnchor(viewport).anchorObject());
+
+  // Scrolling the iframe should clear the anchor on the main frame.
+  frameDocument.view()->setScrollPosition(DoublePoint(0.0, 1000),
+                                          ProgrammaticScroll);
+  EXPECT_EQ(nullptr, scrollAnchor(viewport).anchorObject());
+}
+
 TEST_F(ScrollAnchorTest, FractionalOffsetsAreRoundedBeforeComparing) {
   setBodyInnerHTML(
       "<style> body { height: 1000px } </style>"