Fold compositing display items into contained drawings if the drawing is a singleton.

third_party/WebKit/Source/core/paint/PaintControllerPaintTest.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 "core/paint/PaintControllerPaintTest.h"
 
 #include "core/layout/LayoutText.h"
 #include "core/layout/line/InlineTextBox.h"
 #include "core/page/FocusController.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ skipping 51 matching lines @@
         TestDisplayItem(layoutView(), documentBackgroundType),
         TestDisplayItem(newFirstTextBox, foregroundType),
         TestDisplayItem(secondTextBox, foregroundType));
 }
 
 TEST_F(PaintControllerPaintTestForSlimmingPaintV2, ChunkIdClientCacheFlag)
 {
     setBodyInnerHTML(
         "<div id='div' style='width: 200px; height: 200px; opacity: 0.5'>"
         "  <div style='width: 100px; height: 100px; background-color: blue'></div>"
+        "  <div style='width: 100px; height: 100px; background-color: blue'></div>"
         "</div>");
     PaintLayer& htmlLayer = *toLayoutBoxModelObject(document().documentElement()->layoutObject())->layer();
     LayoutBlock& div = *toLayoutBlock(getLayoutObjectByElementId("div"));
     LayoutObject& subDiv = *div.firstChild();
-
-    EXPECT_DISPLAY_LIST(rootPaintController().getDisplayItemList(), 6,
+    LayoutObject& subDiv2 = *subDiv.nextSibling();
+    EXPECT_DISPLAY_LIST(rootPaintController().getDisplayItemList(), 7,
         TestDisplayItem(layoutView(), documentBackgroundType),
         TestDisplayItem(htmlLayer, DisplayItem::Subsequence),
         TestDisplayItem(div, DisplayItem::BeginCompositing),
         TestDisplayItem(subDiv, backgroundType),
+        TestDisplayItem(subDiv2, backgroundType),
         TestDisplayItem(div, DisplayItem::EndCompositing),
         TestDisplayItem(htmlLayer, DisplayItem::EndSubsequence));
 
     const EffectPaintPropertyNode* effectNode = div.objectPaintProperties()->effect();
     EXPECT_EQ(0.5f, effectNode->opacity());
     const PaintChunk& chunk = rootPaintController().paintChunks()[1];
     EXPECT_EQ(*div.layer(), chunk.id->client);
     EXPECT_EQ(effectNode, chunk.properties.effect.get());
 
     EXPECT_FALSE(div.layer()->isJustCreated());
     // Client used by only paint chunks and non-cachaeable display items but not by any
     // cacheable display items won't be marked as validly cached.
     EXPECT_FALSE(rootPaintController().clientCacheIsValid(*div.layer()));
     EXPECT_FALSE(rootPaintController().clientCacheIsValid(div));
     EXPECT_TRUE(rootPaintController().clientCacheIsValid(subDiv));
 }
 
+TEST_F(PaintControllerPaintTestForSlimmingPaintV2, CompositingFold)
+{
+    setBodyInnerHTML(
+        "<div id='div' style='width: 200px; height: 200px; opacity: 0.5'>"
+        "  <div style='width: 100px; height: 100px; background-color: blue'></div>"
+        "</div>");
+    PaintLayer& htmlLayer = *toLayoutBoxModelObject(document().documentElement()->layoutObject())->layer();
+    LayoutBlock& div = *toLayoutBlock(getLayoutObjectByElementId("div"));
+    LayoutObject& subDiv = *div.firstChild();
+
+    EXPECT_DISPLAY_LIST(rootPaintController().getDisplayItemList(), 4,
+        TestDisplayItem(layoutView(), documentBackgroundType),
+        TestDisplayItem(htmlLayer, DisplayItem::Subsequence),
+        // The begin and end compositing display items have been folded into this one.
+        TestDisplayItem(subDiv, backgroundType),
+        TestDisplayItem(htmlLayer, DisplayItem::EndSubsequence));
+}
+
+
 } // namespace blink