Early-out from the prepaint tree walk

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

 // Copyright 2015 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/LayoutTestHelper.h"
 #include "core/layout/LayoutTreeAsText.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintPropertyTreePrinter.h"
 #include "platform/graphics/paint/GeometryMapper.h"
@@ skipping 2911 matching lines @@
   EXPECT_TRUE(childLayoutView->descendantNeedsPaintPropertyUpdate());
   EXPECT_TRUE(innerDivWithTransform->needsPaintPropertyUpdate());
   EXPECT_FALSE(innerDivWithTransform->descendantNeedsPaintPropertyUpdate());
 
   // After a lifecycle update, no nodes should need a descendant update.
   frameView->updateAllLifecyclePhases();
   EXPECT_FALSE(document().layoutView()->descendantNeedsPaintPropertyUpdate());
   EXPECT_FALSE(divWithTransform->descendantNeedsPaintPropertyUpdate());
   EXPECT_FALSE(childLayoutView->descendantNeedsPaintPropertyUpdate());
   EXPECT_FALSE(innerDivWithTransform->descendantNeedsPaintPropertyUpdate());
+
+  // A child frame marked as needing a paint property update should not be
+  // skipped if the owning layout tree does not need an update.
+  FrameView* childFrameView = childDocument().view();
+  childFrameView->setNeedsPaintPropertyUpdate();
+  EXPECT_TRUE(document().layoutView()->descendantNeedsPaintPropertyUpdate());
+  frameView->updateAllLifecyclePhases();
+  EXPECT_FALSE(document().layoutView()->descendantNeedsPaintPropertyUpdate());
+  EXPECT_FALSE(frameView->needsPaintPropertyUpdate());
+  EXPECT_FALSE(childFrameView->needsPaintPropertyUpdate());
 }
 
 TEST_P(PaintPropertyTreeBuilderTest, UpdatingFrameViewContentClip) {
   setBodyInnerHTML("hello world.");
   EXPECT_EQ(FloatRoundedRect(0, 0, 800, 600), frameContentClip()->clipRect());
   document().view()->resize(800, 599);
   document().view()->updateAllLifecyclePhases();
   EXPECT_EQ(FloatRoundedRect(0, 0, 800, 599), frameContentClip()->clipRect());
   document().view()->resize(800, 600);
   document().view()->updateAllLifecyclePhases();
   EXPECT_EQ(FloatRoundedRect(0, 0, 800, 600), frameContentClip()->clipRect());
   document().view()->resize(5, 5);
   document().view()->updateAllLifecyclePhases();
   EXPECT_EQ(FloatRoundedRect(0, 0, 5, 5), frameContentClip()->clipRect());
 }
 
 }  // namespace blink