Implement Paint Containment

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

+// Copyright 2014 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 "config.h"
+
+#include "core/layout/LayoutBlock.h"
+#include "core/layout/LayoutInline.h"
+#include "core/layout/LayoutTestHelper.h"
+#include "core/paint/PaintLayer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+class PaintContainmentTest : public RenderingTest {
+};
+
+static void checkIsClippingStackingContextAndContainer(LayoutBoxModelObject& obj)
+{
+    EXPECT_TRUE(obj.canContainFixedPositionObjects());
+    EXPECT_TRUE(obj.hasClipRelatedProperty());

[chrishtr, 2015/12/11 23:39:19]

EXPECT_TRUE(obj.style()->containsPaint())

+
+    // TODO(leviw): Ideally, we wouldn't require a paint layer to handle the clipping
+    // and stacking performed by paint containment.
+    ASSERT(obj.layer());
+    PaintLayer* layer = obj.layer();
+    EXPECT_TRUE(layer->stackingNode() && layer->stackingNode()->isStackingContext());
+}
+
+TEST_F(PaintContainmentTest, BlockPaintContainment)
+{
+    setBodyInnerHTML("<div id='div' style='contain: paint'></div>");
+    Element* div = document().getElementById(AtomicString("div"));
+    ASSERT(div);
+    LayoutObject* obj = div->layoutObject();
+    ASSERT(obj && obj->isLayoutBlock());
+    LayoutBlock& block = toLayoutBlock(*obj);
+    EXPECT_TRUE(block.createsNewFormattingContext());
+    EXPECT_FALSE(block.canBeScrolledAndHasScrollableArea());
+    checkIsClippingStackingContextAndContainer(block);
+}
+
+TEST_F(PaintContainmentTest, InlinePaintContainment)
+{
+    setBodyInnerHTML("<div><span id='test' style='contain: paint'>Foo</span></div>");
+    Element* span = document().getElementById(AtomicString("test"));
+    ASSERT(span);
+    LayoutObject* obj = span->layoutObject();
+    ASSERT(obj && obj->isInline());
+    LayoutInline& layoutInline = toLayoutInline(*obj);
+    checkIsClippingStackingContextAndContainer(layoutInline);
+}
+
+}