WIP: Prune 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 2601 matching lines @@
   EXPECT_FALSE(frameScroll()->threadedScrollingDisabled());
   EXPECT_FALSE(overflowA->layoutObject()
                    ->paintProperties()
                    ->scroll()
                    ->threadedScrollingDisabled());
 
   document().settings()->setThreadedScrollingEnabled(false);
   // TODO(pdr): The main thread scrolling setting should invalidate properties.
   document().view()->setNeedsPaintPropertyUpdate();
   overflowA->layoutObject()->setNeedsPaintPropertyUpdate();
+  overflowA->layoutObject()->setAllAncestorsNeedPaintPropertyUpdate();
   document().view()->updateAllLifecyclePhases();
 
   EXPECT_TRUE(frameScroll()->threadedScrollingDisabled());
   EXPECT_TRUE(overflowA->layoutObject()
                   ->paintProperties()
                   ->scroll()
                   ->threadedScrollingDisabled());
 }
 
 TEST_P(PaintPropertyTreeBuilderTest,
@@ skipping 254 matching lines @@
       childProperties->localBorderBoxProperties()->propertyTreeState;
   EXPECT_EQ(framePreTranslation(),
             childProperties->paintOffsetTranslation()->parent());
   EXPECT_EQ(childProperties->paintOffsetTranslation(),
             childPaintState.transform());
   // This will change once we added clip expansion node.
   EXPECT_EQ(filterProperties->effect()->outputClip(), childPaintState.clip());
   EXPECT_EQ(filterProperties->effect(), childPaintState.effect());
 }
 
+TEST_P(PaintPropertyTreeBuilderTest, DescendantNeedsUpdateAcrossFrames) {
+  setBodyInnerHTML(
+      "<style>body { margin: 0; }</style>"
+      "<div id='divWithTransform' style='transform: translate3d(1px,2px,3px);'>"
+      "  <iframe style='border: 7px solid black'></iframe>"
+      "</div>");
+  setChildFrameHTML(
+      "<style>body { margin: 0; }</style><div id='transform' style='transform: "
+      "translate3d(4px, 5px, 6px); width: 100px; height: 200px'></div>");
+
+  FrameView* frameView = document().view();
+  frameView->updateAllLifecyclePhases();
+
+  LayoutObject* divWithTransform =
+      document().getElementById("divWithTransform")->layoutObject();
+  LayoutObject* childLayoutView = childDocument().layoutView();
+  LayoutObject* innerDivWithTransform =
+      childDocument().getElementById("transform")->layoutObject();
+
+  // Initially, no objects should need a descendant update.
+  EXPECT_FALSE(document().layoutView()->descendantNeedsPaintPropertyUpdate());
+  EXPECT_FALSE(divWithTransform->descendantNeedsPaintPropertyUpdate());
+  EXPECT_FALSE(childLayoutView->descendantNeedsPaintPropertyUpdate());
+  EXPECT_FALSE(innerDivWithTransform->descendantNeedsPaintPropertyUpdate());
+
+  // Marking the child div as needing a paint property update should propagate
+  // up the tree and across frames.
+  innerDivWithTransform->setNeedsPaintPropertyUpdate();
+  EXPECT_TRUE(document().layoutView()->descendantNeedsPaintPropertyUpdate());
+  EXPECT_TRUE(divWithTransform->descendantNeedsPaintPropertyUpdate());
+  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());
+}
+
 }  // namespace blink