Descend into node with overflow and floating content

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

 // 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/layout/LayoutBox.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/paint/PaintLayerScrollableArea.h"
 #include "platform/testing/HistogramTester.h"
@@ skipping 245 matching lines @@
     EXPECT_EQ(relPos->layoutObject(), scrollAnchor(scroller).anchorObject());
 
     scrollerElement->setAttribute(HTMLNames::styleAttr, "position: relative");
     scroller->scrollBy(DoubleSize(0, 25), UserScroll);
     setHeight(relPos, 125);
 
     // When the scroller is position:relative, the anchor may be position:absolute.
     EXPECT_EQ(absPos->layoutObject(), scrollAnchor(scroller).anchorObject());
 }
 
+// Test that we descend into zero-height containers that have overflowing content.
+TEST_F(ScrollAnchorTest, DescendsIntoContainerWithOverflow)
+{
+    setBodyInnerHTML(
+        "<style>"
+        "    body { height: 1000; }"
+        "    #outer { width: 300px; }"
+        "    #zeroheight { height: 0px; }"
+        "    #changer { height: 100px; background-color: red; }"
+        "    #bottom { margin-top: 600px; }"
+        "</style>"
+        "<div id='outer'>"
+        "    <div id='zeroheight'>"
+        "      <div id='changer'></div>"
+        "      <div id='bottom'>bottom</div>"
+        "    </div>"
+        "</div>");
+
+    ScrollableArea* viewport = layoutViewport();
+
+    scrollLayoutViewport(DoubleSize(0, 200));
+    setHeight(document().getElementById("changer"), 200);
+
+    EXPECT_EQ(300, viewport->scrollPosition().y());
+    EXPECT_EQ(document().getElementById("bottom")->layoutObject(),
+        scrollAnchor(viewport).anchorObject());
+}
+
+// Test that we descend into zero-height containers that have floating content.
+TEST_F(ScrollAnchorTest, DescendsIntoContainerWithFloat)
+{
+    setBodyInnerHTML(
+        "<style>"
+        "    body { height: 1000; }"
+        "    #outer { width: 300px; }"
+        "    #outer:after { content: ' '; clear:both; display: table; }"
+        "    #float {"
+        "         float: left; background-color: #ccc;"
+        "         height: 500px; width: 100%;"
+        "    }"
+        "    #inner { height: 21px; background-color:#7f0; }"
+        "</style>"
+        "<div id='outer'>"
+        "    <div id='zeroheight'>"
+        "      <div id='float'>"
+        "         <div id='inner'></div>"
+        "      </div>"
+        "    </div>"
+        "</div>");
+
+    EXPECT_EQ(0, toLayoutBox(document().getElementById("zeroheight")->layoutObject())->size().height());
+
+    ScrollableArea* viewport = layoutViewport();
+
+    scrollLayoutViewport(DoubleSize(0, 200));
+    setHeight(document().getElementById("float"), 600);
+
+    EXPECT_EQ(200, viewport->scrollPosition().y());
+    EXPECT_EQ(document().getElementById("float")->layoutObject(),
+        scrollAnchor(viewport).anchorObject());
+}
+
 class ScrollAnchorCornerTest : public ScrollAnchorTest {
 protected:
     void checkCorner(const AtomicString& id, Corner corner, DoublePoint startPos, DoubleSize expectedAdjustment)
     {
         ScrollableArea* viewport = layoutViewport();
         Element* element = document().getElementById(id);
 
         viewport->setScrollPosition(startPos, UserScroll);
         element->setAttribute(HTMLNames::classAttr, "big");
         update();
@@ skipping 129 matching lines @@
         "<div id=c></div>"
         "<div id=d></div>");
 
     checkCorner("b", Corner::TopRight, DoublePoint(-20,  20),  DoubleSize(0, 0));
     checkCorner("a", Corner::TopRight, DoublePoint(-420, 20),  DoubleSize(400, 0));
     checkCorner("d", Corner::TopRight, DoublePoint(-20,  320), DoubleSize(0, -300));
     checkCorner("c", Corner::TopRight, DoublePoint(-420, 320), DoubleSize(400, -300));
 }
 
 }