Generate scroll/clip display item hierarchy for SPv2

Source/core/paint/DisplayItemListPaintTest.cpp

Index: Source/core/paint/DisplayItemListPaintTest.cpp
diff --git a/Source/core/paint/DisplayItemListPaintTest.cpp b/Source/core/paint/DisplayItemListPaintTest.cpp
index 675ea5ffb27eea969c2ccf295e7789ae21b5330d..740e19775e2dad18664695d67c1ffc09106972f7 100644
--- a/Source/core/paint/DisplayItemListPaintTest.cpp
+++ b/Source/core/paint/DisplayItemListPaintTest.cpp
@@ -228,7 +228,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, FullDocumentPaintingWithCaret
 
     document().view()->updateAllLifecyclePhases();
 
-    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 4,
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 5,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(textInlineBox, DisplayItem::paintPhaseToDrawingType(PaintPhaseForeground)),
@@ -237,7 +238,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, FullDocumentPaintingWithCaret
     div.focus();
     document().view()->updateAllLifecyclePhases();
 
-    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 5,
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 6,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(textInlineBox, DisplayItem::paintPhaseToDrawingType(PaintPhaseForeground)),
@@ -257,7 +259,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, InlineRelayout)
 
     document().view()->updateAllLifecyclePhases();
 
-    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 4,
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 5,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(firstTextBox, DisplayItem::paintPhaseToDrawingType(PaintPhaseForeground)),
@@ -270,7 +273,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, InlineRelayout)
     InlineTextBox& newFirstTextBox = *newText.firstTextBox();
     InlineTextBox& secondTextBox = *newText.firstTextBox()->nextTextBox();
 
-    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 5,
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 6,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(newFirstTextBox, DisplayItem::paintPhaseToDrawingType(PaintPhaseForeground)),
@@ -296,7 +300,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, CachedSubsequence)
     LayoutObject& container2 = *document().getElementById("container2")->layoutObject();
     LayoutObject& content2 = *document().getElementById("content2")->layoutObject();
 
-    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 11,
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 12,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(container1, DisplayItem::BeginSubsequence),
@@ -312,7 +317,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, CachedSubsequence)
     toHTMLElement(content1.node())->setAttribute(HTMLNames::styleAttr, "width: 100px; height: 100px; background-color: green");
     updateLifecyclePhasesToPaintForSlimmingPaintV2Clean();
 
-    EXPECT_DISPLAY_LIST_WITH_CACHED_RED_FILL_IN_DEBUG(newDisplayItemsBeforeUpdate(), 8,
+    EXPECT_DISPLAY_LIST_WITH_CACHED_RED_FILL_IN_DEBUG(newDisplayItemsBeforeUpdate(), 9,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::drawingTypeToCachedDrawingType(DisplayItem::BoxDecorationBackground)),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(container1, DisplayItem::BeginSubsequence),
@@ -324,7 +330,8 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, CachedSubsequence)
 
     compositeForSlimmingPaintV2();
 
-    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 11,
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 12,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
         TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
         TestDisplayItem(html, DisplayItem::BeginSubsequence),
         TestDisplayItem(container1, DisplayItem::BeginSubsequence),
@@ -338,4 +345,65 @@ TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, CachedSubsequence)
         TestDisplayItem(html, DisplayItem::EndSubsequence));
 }
 
+TEST_F(DisplayItemListPaintTestForSlimmingPaintV2, OverflowClipHierarchy)
+{
+    setBodyInnerHTML(
+        "<div id='scroller1' style='overflow: hidden; width: 100px; height: 100px;'>"
+        "  <div id='scroller2' style='overflow: hidden; width: 200px; height: 200px;'>"
+        "    normal flow"
+        "    <div id='positioned' style='position:relative; z-index: -1; width: 300px; height: 300px; border: 1px dotted black;'></div>"

[pdr., 2015/09/03 06:16:59]

Is z-index: -1 needed here?

[trchen, 2015/09/04 06:10:15]

Not important. Removal done.

+        "  </div>"
+        "</div>");
+    document().view()->updateAllLifecyclePhases();

[pdr., 2015/09/03 06:16:59]

This isn't necessary as setBodyInnerHTML (confusingly) does it.

[trchen, 2015/09/04 06:10:15]

Done.

+
+    LayoutView& layoutView = *document().layoutView();
+    LayoutObject& html = *document().documentElement()->layoutObject();
+    LayoutObject& scroller1 = *document().getElementById("scroller1")->layoutObject();
+    LayoutObject& scroller2 = *document().getElementById("scroller2")->layoutObject();
+    InlineTextBox& normalFlow = *static_cast<LayoutText*>(scroller2.slowFirstChild()->slowFirstChild())->firstTextBox();
+    LayoutObject& positioned = *document().getElementById("positioned")->layoutObject();
+
+    static_cast<LayoutBox&>(scroller1).scrollToOffset(DoubleSize(12, 34));
+    static_cast<LayoutBox&>(scroller2).scrollToOffset(DoubleSize(56, 78));
+    document().view()->updateAllLifecyclePhases();
+
+    EXPECT_DISPLAY_LIST_WITH_RED_FILL_IN_DEBUG(rootDisplayItemList().displayItems(), 32,
+        TestDisplayItem(layoutView, DisplayItem::FixedPositionContainer),
+        TestDisplayItem(layoutView, DisplayItem::BoxDecorationBackground),
+        TestDisplayItem(html, DisplayItem::BeginSubsequence),
+
+            TestDisplayItem(scroller1, DisplayItem::ClipDescendantStackingContext),
+                TestDisplayItem(scroller1, DisplayItem::paintPhaseToScrollType(PaintPhaseBlockBackground)),
+                    TestDisplayItem(scroller2, DisplayItem::ClipDescendantStackingContext),
+                        TestDisplayItem(scroller2, DisplayItem::paintPhaseToScrollType(PaintPhaseBlockBackground)),
+                            TestDisplayItem(positioned, DisplayItem::BeginSubsequence),
+                                TestDisplayItem(positioned, DisplayItem::BoxDecorationBackground),
+                            TestDisplayItem(positioned, DisplayItem::EndSubsequence),
+                        TestDisplayItem(scroller2, DisplayItem::scrollTypeToEndScrollType(DisplayItem::paintPhaseToScrollType(PaintPhaseBlockBackground))),
+                    TestDisplayItem(scroller2, DisplayItem::clipTypeToEndClipType(DisplayItem::ClipDescendantStackingContext)),
+                TestDisplayItem(scroller1, DisplayItem::scrollTypeToEndScrollType(DisplayItem::paintPhaseToScrollType(PaintPhaseBlockBackground))),
+            TestDisplayItem(scroller1, DisplayItem::clipTypeToEndClipType(DisplayItem::ClipDescendantStackingContext)),
+
+            TestDisplayItem(scroller1, DisplayItem::paintPhaseToClipBoxType(PaintPhaseForeground)),
+                TestDisplayItem(scroller1, DisplayItem::paintPhaseToScrollType(PaintPhaseForeground)),
+                    TestDisplayItem(scroller2, DisplayItem::paintPhaseToClipBoxType(PaintPhaseForeground)),
+                        TestDisplayItem(scroller2, DisplayItem::paintPhaseToScrollType(PaintPhaseForeground)),
+                            TestDisplayItem(normalFlow, DisplayItem::paintPhaseToDrawingType(PaintPhaseForeground)),
+                        TestDisplayItem(scroller2, DisplayItem::scrollTypeToEndScrollType(DisplayItem::paintPhaseToScrollType(PaintPhaseForeground))),
+                    TestDisplayItem(scroller2, DisplayItem::clipTypeToEndClipType(DisplayItem::paintPhaseToClipBoxType(PaintPhaseForeground))),
+                TestDisplayItem(scroller1, DisplayItem::scrollTypeToEndScrollType(DisplayItem::paintPhaseToScrollType(PaintPhaseForeground))),
+            TestDisplayItem(scroller1, DisplayItem::clipTypeToEndClipType(DisplayItem::paintPhaseToClipBoxType(PaintPhaseForeground))),
+
+            TestDisplayItem(scroller1, DisplayItem::BeginSubsequence),
+                TestDisplayItem(scroller1, DisplayItem::ClipDescendantStackingContext),
+                    TestDisplayItem(scroller1, DisplayItem::paintPhaseToScrollType(PaintPhaseBlockBackground)),
+                        TestDisplayItem(scroller2, DisplayItem::BeginSubsequence),
+                        TestDisplayItem(scroller2, DisplayItem::EndSubsequence),
+                    TestDisplayItem(scroller1, DisplayItem::scrollTypeToEndScrollType(DisplayItem::paintPhaseToScrollType(PaintPhaseBlockBackground))),
+                TestDisplayItem(scroller1, DisplayItem::clipTypeToEndClipType(DisplayItem::ClipDescendantStackingContext)),
+            TestDisplayItem(scroller1, DisplayItem::EndSubsequence),
+
+        TestDisplayItem(html, DisplayItem::EndSubsequence));
+}
+

[pdr., 2015/09/03 06:16:59]

Can you add a second test of the following scenario (from
https://docs.google.com/document/d/1cOPCJufeXU7ifkb7kn3zQL8Bf7VZkS-KDGm3IyzXe...):
<div id='scroller1' style='overflow: scroll; width: 100px; height: 100px;'>
  <div id='scroller2' style='overflow: scroll; width: 200px; height: 200px;'>
    <div id='positioned' style='top: 10px; left: 10px; position:relative; width:
300px; height: 300px; outline: 3px dotted black; background-color:
green;'></div>
  </div>
</div>

I would expect this to generate two nested clip/scroll trees with one containing
the positioned background, and one the positioned outline (plus some scrollbars
that can be ignored). I tried this test and didn't see the outline phase working
properly, which may mean recursivelyScrollAndPaintChildLayer doesn't handle
phases properly, or my test was just bad.

[trchen, 2015/09/04 06:10:15]

I ran your test case locally, the drawing display item for outline is appended
right after the box decoration background, sharing the same pairs of clip/scroll
tree. This is expected because position:relative makes the block a pseudo
stacking context.

If we remove position:relative, we shall see separate trees for each paint
phase. Will add a test for it.

 } // namespace blink