Fix GraphicsLayerUpdater::UpdateContext::compositingContainer() for corner cases

third_party/WebKit/Source/core/paint/PaintLayerTest.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerTest.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerTest.cpp b/third_party/WebKit/Source/core/paint/PaintLayerTest.cpp
index 3341e981fd596ea4b88693315bfe66f40a99fd81..7b0f5bb6c7afcbb9ffabb023ebd933a2b349ded1 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerTest.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerTest.cpp
@@ -516,7 +516,7 @@ TEST_P(PaintLayerTest, PaintInvalidationOnCompositedScroll) {
   EXPECT_EQ(LayoutRect(0, 30, 50, 5), content->visualRect());
 }
 
-TEST_P(PaintLayerTest, CompositingContainerFloat) {
+TEST_P(PaintLayerTest, CompositingContainerFloatUnderInline) {
   enableCompositing();
   setBodyInnerHTML(
       "<div id='compositedContainer' style='position: relative;"
@@ -547,6 +547,39 @@ TEST_P(PaintLayerTest, CompositingContainerFloat) {
   }
 }
 
+TEST_P(PaintLayerTest, CompositingContainerUnderFloatUnderInline) {

[Xianzhu, 2017/03/30 22:23:12]

This test also passes without any real code change.

+  enableCompositing();
+  setBodyInnerHTML(
+      "<div id='compositedContainer' style='position: relative;"
+      "    will-change: transform'>"
+      "  <div id='containingBlock' style='position: relative; z-index: 0'>"
+      "    <div style='backface-visibility: hidden'></div>"
+      "    <span id='span'"
+      "        style='clip-path: polygon(0px 15px, 0px 54px, 100px 0px)'>"
+      "      <div style='float: right'>"
+      "        <div id='target' style='position: relative'></div>"
+      "      </div>"
+      "    </span>"
+      "  </div>"
+      "</div>");
+
+  PaintLayer* target =
+      toLayoutBoxModelObject(getLayoutObjectByElementId("target"))->layer();
+  PaintLayer* span =
+      toLayoutBoxModelObject(getLayoutObjectByElementId("span"))->layer();
+  EXPECT_EQ(span, target->compositingContainer());
+  PaintLayer* compositedContainer =
+      toLayoutBoxModelObject(getLayoutObjectByElementId("compositedContainer"))
+          ->layer();
+
+  // enclosingLayerWithCompositedLayerMapping is not needed or applicable to
+  // SPv2.
+  if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+    EXPECT_EQ(compositedContainer,
+              target->enclosingLayerWithCompositedLayerMapping(ExcludeSelf));
+  }
+}
+
 TEST_P(PaintLayerTest, FloatLayerAndAbsoluteUnderInlineLayer) {
   setBodyInnerHTML(
       "<div id='container' style='position: absolute; top: 20px; left: 20px'>"