Compute sticky position constraints without considering transforms.

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

 // 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 "core/layout/LayoutBoxModelObject.h"
 
 #include "core/html/HTMLElement.h"
 #include "core/layout/ImageQualityController.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/page/scrolling/StickyPositionScrollingConstraints.h"
@@ skipping 32 matching lines @@
     ASSERT_EQ(scroller->layer(), sticky->layer()->ancestorOverflowLayer());
 
     const StickyPositionScrollingConstraints& constraints = scroller->getScrollableArea()->stickyConstraintsMap().get(sticky->layer());
     ASSERT_EQ(0.f, constraints.topOffset());
 
     // The coordinates of the constraint rects should all be with respect to the unscrolled scroller.
     ASSERT_EQ(IntRect(15, 115, 170, 370), enclosingIntRect(getScrollContainerRelativeContainingBlockRect(constraints)));
     ASSERT_EQ(IntRect(15, 115, 100, 100), enclosingIntRect(getScrollContainerRelativeStickyBoxRect(constraints)));
 }
 
+// Verifies that the sticky constraints are not affected by transforms
+TEST_F(LayoutBoxModelObjectTest, StickyPositionTransforms)
+{
+    setBodyInnerHTML("<style>#sticky { position: sticky; top: 0; width: 100px; height: 100px; transform: scale(2); transform-origin: top left; }"
+        "#container { box-sizing: border-box; position: relative; top: 100px; height: 400px; width: 200px; padding: 10px; border: 5px solid black; transform: scale(2); transform-origin: top left; }"
+        "#scroller { height: 100px; overflow: auto; position: relative; top: 200px; }"
+        ".spacer { height: 1000px; }</style>"
+        "<div id='scroller'><div id='container'><div id='sticky'></div></div><div class='spacer'></div></div>");
+    LayoutBoxModelObject* scroller = toLayoutBoxModelObject(getLayoutObjectByElementId("scroller"));
+    scroller->getScrollableArea()->scrollToYOffset(50);
+    ASSERT_EQ(50.0, scroller->getScrollableArea()->scrollYOffset());
+    LayoutBoxModelObject* sticky = toLayoutBoxModelObject(getLayoutObjectByElementId("sticky"));
+    sticky->updateStickyPositionConstraints();
+    ASSERT_EQ(scroller->layer(), sticky->layer()->ancestorOverflowLayer());
+
+    const StickyPositionScrollingConstraints& constraints = scroller->getScrollableArea()->stickyConstraintsMap().get(sticky->layer());
+    ASSERT_EQ(0.f, constraints.topOffset());
+
+    // The coordinates of the constraint rects should all be with respect to the unscrolled scroller.
+    ASSERT_EQ(IntRect(15, 115, 170, 370), enclosingIntRect(getScrollContainerRelativeContainingBlockRect(constraints)));
+    ASSERT_EQ(IntRect(15, 115, 100, 100), enclosingIntRect(getScrollContainerRelativeStickyBoxRect(constraints)));
+}
+
 // Verifies that the sticky constraints are correctly computed.
 TEST_F(LayoutBoxModelObjectTest, StickyPositionPercentageStyles)
 {
     setBodyInnerHTML("<style>#sticky { position: sticky; margin-top: 10%; top: 0; width: 100px; height: 100px; }"
         "#container { box-sizing: border-box; position: relative; top: 100px; height: 400px; width: 250px; padding: 5%; border: 5px solid black; }"
         "#scroller { width: 400px; height: 100px; overflow: auto; position: relative; top: 200px; }"
         ".spacer { height: 1000px; }</style>"
         "<div id='scroller'><div id='container'><div id='sticky'></div></div><div class='spacer'></div></div>");
     LayoutBoxModelObject* scroller = toLayoutBoxModelObject(getLayoutObjectByElementId("scroller"));
     scroller->getScrollableArea()->scrollToYOffset(50);
@@ skipping 44 matching lines @@
     ASSERT_EQ(50.0, scroller->getScrollableArea()->scrollYOffset());
     LayoutBoxModelObject* sticky = toLayoutBoxModelObject(getLayoutObjectByElementId("sticky"));
     sticky->updateStickyPositionConstraints();
     ASSERT_EQ(scroller->layer(), sticky->layer()->ancestorOverflowLayer());
 
     const StickyPositionScrollingConstraints& constraints = scroller->getScrollableArea()->stickyConstraintsMap().get(sticky->layer());
     ASSERT_EQ(IntRect(15, 115, 170, 370), enclosingIntRect(getScrollContainerRelativeContainingBlockRect(constraints)));
     ASSERT_EQ(IntRect(15, 165, 100, 100), enclosingIntRect(getScrollContainerRelativeStickyBoxRect(constraints)));
 }
 } // namespace blink