Fix Compositing of Opaque Scrolling Layers and Add Tests

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.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/layout/compositing/CompositedLayerMapping.h"
 
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutBoxModelObject.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/api/LayoutViewItem.h"
@@ skipping 29 matching lines @@
         return CompositedLayerMapping::interestRectChangedEnoughToRepaint(previousInterestRect, newInterestRect, layerSize);
     }
 
     IntRect previousInterestRect(const GraphicsLayer* graphicsLayer)
     {
         return graphicsLayer->m_previousInterestRect;
     }
 
     bool shouldPaintBackgroundOntoScrollingContentsLayer(const char* elementId)
     {
-        CompositedLayerMapping* mapping = toLayoutBlock(getLayoutObjectByElementId(elementId))->layer()->compositedLayerMapping();
-        return mapping->shouldPaintBackgroundOntoScrollingContentsLayer();
+        PaintLayer* paintLayer = toLayoutBlock(getLayoutObjectByElementId(elementId))->layer();
+        return paintLayer->shouldPaintBackgroundOntoScrollingContentsLayer();

[flackr, 2016/08/30 21:14:49]

We should probably move the tests rather than have CompositedLayerMappingTest
test PaintLayer.

[Stephen Chennney, 2016/08/31 20:50:20]

Done.

     }
 
 private:
     void SetUp() override
     {
         RenderingTest::SetUp();
         enableCompositing();
     }
 
     void TearDown() override
@@ skipping 605 matching lines @@
     // Sixth scroller can paint background into scrolling contents layer because the image is locally attached and even though
     // the color is not, it is filled to the padding box so it will be drawn the same as a locally attached background.
     EXPECT_TRUE(shouldPaintBackgroundOntoScrollingContentsLayer("scroller6"));
 
     // Seventh scroller cannot paint background into scrolling contents layer because the color is filled to the content
     // box and we have padding so it is not equivalent to a locally attached background.
     EXPECT_FALSE(shouldPaintBackgroundOntoScrollingContentsLayer("scroller7"));
 }
 
 } // namespace blink