Handle nested position:sticky elements correctly (compositor)

third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
index ce5ddb73319dffff4ac917288477a1df61a414b2..bb3671debae01c867c8f08d79ca4ad76bd3162f3 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
@@ -271,36 +271,4 @@ TEST_F(CompositingReasonFinderTest, RequiresCompositingForEffectAnimation) {
       CompositingReasonFinder::requiresCompositingForEffectAnimation(*style));
 }
 
-TEST_F(CompositingReasonFinderTest, DoNotCompositeNestedSticky) {
-  ScopedCompositeFixedPositionForTest compositeFixedPosition(true);
-
-  setBodyInnerHTML(

[chrishtr, 2017/03/20 17:24:52]

Please re-add this test to execise the opposite condition (that nested stickies
are composited).

[smcgruer, 2017/03/21 13:54:54]

Done.

-      "<style>.scroller { overflow: scroll; height: 200px; width: 100px; }"
-      ".container { height: 500px; }"
-      ".opaque { background-color: white; contain: paint; }"
-      "#outerSticky { height: 50px; position: sticky; top: 0px; }"
-      "#innerSticky { height: 20px; position: sticky; top: 25px; }</style>"
-      "<div class='scroller'>"
-      "  <div class='container'>"
-      "    <div id='outerSticky' class='opaque'>"
-      "      <div id='innerSticky' class='opaque'></div>"
-      "    </div>"
-      "  </div>"
-      "</div>");
-  document().view()->updateAllLifecyclePhases();
-
-  Element* outerSticky = document().getElementById("outerSticky");
-  PaintLayer* outerStickyLayer =
-      toLayoutBoxModelObject(outerSticky->layoutObject())->layer();
-  ASSERT_TRUE(outerStickyLayer);
-
-  Element* innerSticky = document().getElementById("innerSticky");
-  PaintLayer* innerStickyLayer =
-      toLayoutBoxModelObject(innerSticky->layoutObject())->layer();
-  ASSERT_TRUE(innerStickyLayer);
-
-  EXPECT_EQ(PaintsIntoOwnBacking, outerStickyLayer->compositingState());
-  EXPECT_EQ(NotComposited, innerStickyLayer->compositingState());
-}
-
 }  // namespace blink