Fix compositingContainer for stacked inlines.

third_party/WebKit/Source/core/paint/PaintLayerTest.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/paint/PaintLayer.h"
 
 #include "core/html/HTMLIFrameElement.h"
 #include "core/layout/LayoutBoxModelObject.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutView.h"
@@ skipping 483 matching lines @@
   EXPECT_EQ(LayoutRect(0, 30, 50, 5), content->visualRect());
 }
 
 TEST_P(PaintLayerTest, CompositingContainerFloat) {
   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 style='clip-path: polygon(0px 15px, 0px 54px, 100px 0px)'>"
+      "    <span id='span'"
+      "        style='clip-path: polygon(0px 15px, 0px 54px, 100px 0px)'>"
       "      <div id='target' style='float: right; position: relative'></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, CompositingContainerFloatingIframe) {
+  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)'>"
+      "      <iframe srcdoc=foo' id='target' style='float: right'></iframe>"

[Xianzhu, 2017/01/19 21:50:02]

Nit: s/foo'/'foo'/

+      "    </span>"
+      "  </div>"
+      "</div>");
+
+  PaintLayer* target =
+      toLayoutBoxModelObject(getLayoutObjectByElementId("target"))->layer();
+
+  // A non-positioned iframe still gets a PaintLayer because PaintLayers are
+  // forced for all LayoutPart objects. However, such PaintLayers are not
+  // stacked.
   PaintLayer* containingBlock =
       toLayoutBoxModelObject(getLayoutObjectByElementId("containingBlock"))
           ->layer();
   EXPECT_EQ(containingBlock, 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));
   }
 }
 
 }  // namespace blink