Implement a paint offset cache for slimming paint v2

Source/core/paint/LayoutObjectDrawingRecorderTest.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 "config.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
 
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutView.h"
 #include "core/paint/DeprecatedPaintLayer.h"
@@ skipping 30 matching lines @@
 
     void TearDown() override
     {
         RuntimeEnabledFeatures::setSlimmingPaintEnabled(m_originalSlimmingPaintEnabled);
     }
 
     LayoutView* m_layoutView;
     bool m_originalSlimmingPaintEnabled;
 };
 
+class LayoutObjectDrawingRecorderTestForSlimmingPaintV2 : public RenderingTest {
+public:
+    LayoutObjectDrawingRecorderTestForSlimmingPaintV2()
+        : m_layoutView(nullptr)
+        , m_originalSlimmingPaintEnabled(RuntimeEnabledFeatures::slimmingPaintEnabled())
+        , m_originalSlimmingPaintV2Enabled(RuntimeEnabledFeatures::slimmingPaintV2Enabled()) { }
+
+protected:
+    LayoutView& layoutView() { return *m_layoutView; }
+    DisplayItemList& rootDisplayItemList() { return *layoutView().layer()->graphicsLayerBacking()->displayItemList(); }
+    const DisplayItems& newDisplayItemsBeforeUpdate() { return rootDisplayItemList().m_newDisplayItems; }
+
+private:
+    void SetUp() override
+    {
+        RuntimeEnabledFeatures::setSlimmingPaintEnabled(true);
+        RuntimeEnabledFeatures::setSlimmingPaintV2Enabled(true);
+
+        RenderingTest::SetUp();
+        enableCompositing();
+
+        m_layoutView = document().view()->layoutView();
+        ASSERT_TRUE(m_layoutView);
+    }
+
+    void TearDown() override
+    {
+        RuntimeEnabledFeatures::setSlimmingPaintEnabled(m_originalSlimmingPaintV2Enabled);
+        RuntimeEnabledFeatures::setSlimmingPaintEnabled(m_originalSlimmingPaintEnabled);
+    }
+
+    LayoutView* m_layoutView;
+    bool m_originalSlimmingPaintEnabled;
+    bool m_originalSlimmingPaintV2Enabled;
+};
+
 namespace {
 
 void drawNothing(GraphicsContext& context, const LayoutView& layoutView, PaintPhase phase, const LayoutRect& bound)
 {
-    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView, phase))
+    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView, phase, LayoutPoint()))
         return;
 
-    LayoutObjectDrawingRecorder drawingRecorder(context, layoutView, phase, bound);
+    LayoutObjectDrawingRecorder drawingRecorder(context, layoutView, phase, bound, LayoutPoint());
 }
 
 void drawRect(GraphicsContext& context, LayoutView& layoutView, PaintPhase phase, const LayoutRect& bound)
 {
-    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView, phase))
+    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView, phase, LayoutPoint()))
         return;
-    LayoutObjectDrawingRecorder drawingRecorder(context, layoutView, phase, bound);
+    LayoutObjectDrawingRecorder drawingRecorder(context, layoutView, phase, bound, LayoutPoint());
     IntRect rect(0, 0, 10, 10);
     context.drawRect(rect);
 }
 
 bool isDrawing(const DisplayItem& item)
 {
     return DisplayItem::isDrawingType(item.type());
 }
 
 bool isCached(const DisplayItem& item)
@@ skipping 48 matching lines @@
 }
 
 template <typename T>
 FloatRect drawAndGetCullRect(DisplayItemList& list, const LayoutObject& layoutObject, const T& bounds)
 {
     list.invalidateAll();
     {
         // Draw some things which will produce a non-null picture.
         GraphicsContext context(&list);
         LayoutObjectDrawingRecorder recorder(
-            context, layoutObject, DisplayItem::BoxDecorationBackground, bounds);
+            context, layoutObject, DisplayItem::BoxDecorationBackground, bounds, LayoutPoint());
         context.drawRect(enclosedIntRect(FloatRect(bounds)));
     }
     list.commitNewDisplayItems();
     const auto& drawing = static_cast<const DrawingDisplayItem&>(list.displayItems()[0]);
     return drawing.picture()->cullRect();
 }
 
 TEST_F(LayoutObjectDrawingRecorderTest, CullRectMatchesProvidedClip)
 {
     // It's safe for the picture's cull rect to be expanded (though doing so
     // excessively may harm performance), but it cannot be contracted.
     // For now, this test expects the two rects to match completely.
     //
     // This rect is chosen so that in the x direction, pixel snapping rounds in
     // the opposite direction to enclosing, and in the y direction, the edges
     // are exactly on a half-pixel boundary. The numbers chosen map nicely to
     // both float and LayoutUnit, to make equality checking reliable.
     FloatRect rect(20.75, -5.5, 5.375, 10);
     EXPECT_EQ(rect, drawAndGetCullRect(rootDisplayItemList(), layoutView(), rect));
     EXPECT_EQ(rect, drawAndGetCullRect(rootDisplayItemList(), layoutView(), LayoutRect(rect)));
 }
 
+TEST_F(LayoutObjectDrawingRecorderTestForSlimmingPaintV2, PaintOffsetCache)
+{
+    GraphicsContext context(&rootDisplayItemList());
+    LayoutRect bounds = layoutView().viewRect();
+    LayoutPoint paintOffset(1, 2);
+
+    rootDisplayItemList().invalidateAll();
+    EXPECT_FALSE(LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView(), PaintPhaseForeground, paintOffset));
+    {
+        LayoutObjectDrawingRecorder drawingRecorder(context, layoutView(), PaintPhaseForeground, bounds, paintOffset);
+        IntRect rect(0, 0, 10, 10);
+        context.drawRect(rect);
+    }
+
+    rootDisplayItemList().commitNewDisplayItems();
+    EXPECT_EQ((size_t)1, rootDisplayItemList().displayItems().size());
+    EXPECT_TRUE(isDrawing(rootDisplayItemList().displayItems()[0]));
+
+    // Ensure we cannot use the cache with a new paint offset.
+    LayoutPoint newPaintOffset(2, 3);
+    EXPECT_FALSE(LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView(), PaintPhaseForeground, newPaintOffset));
+
+    // Test that a new paint offset is recorded.
+    {
+        LayoutObjectDrawingRecorder drawingRecorder(context, layoutView(), PaintPhaseForeground, bounds, newPaintOffset);
+        IntRect rect(0, 0, 10, 10);
+        context.drawRect(rect);
+    }
+
+    rootDisplayItemList().commitNewDisplayItems();
+    EXPECT_EQ((size_t)1, rootDisplayItemList().displayItems().size());
+    EXPECT_TRUE(isDrawing(rootDisplayItemList().displayItems()[0]));
+
+    // Ensure the old paint offset cannot be used.
+    EXPECT_FALSE(LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView(), PaintPhaseForeground, paintOffset));
+
+    // Ensure the new paint offset can be used.
+    EXPECT_TRUE(LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView(), PaintPhaseForeground, newPaintOffset));
+    rootDisplayItemList().commitNewDisplayItems();
+    EXPECT_EQ((size_t)1, rootDisplayItemList().displayItems().size());
+    EXPECT_TRUE(isDrawing(rootDisplayItemList().displayItems()[0]));
+}
+
 } // namespace
 } // namespace blink