[SP] Save and restore slimming paint enabled state in SP-specific unit tests.

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 3eb3e6f5e8ac61eb81700e6925620d4ce0f1ae42..08843ac49d5da69c012c59e621ac7c248497c5a0 100644
--- a/Source/core/paint/DisplayItemListPaintTest.cpp
+++ b/Source/core/paint/DisplayItemListPaintTest.cpp
@@ -26,7 +26,8 @@ namespace blink {
 class DisplayItemListPaintTest : public RenderingTest {
 public:
     DisplayItemListPaintTest()
-        : m_layoutView(nullptr) { }
+        : m_layoutView(nullptr)
+        , m_originalSlimmingPaintEnabled(RuntimeEnabledFeatures::slimmingPaintEnabled()) { }
 
 protected:
     LayoutView& layoutView() { return *m_layoutView; }
@@ -47,10 +48,11 @@ private:
 
     virtual void TearDown() override
     {
-        RuntimeEnabledFeatures::setSlimmingPaintEnabled(false);
+        RuntimeEnabledFeatures::setSlimmingPaintEnabled(m_originalSlimmingPaintEnabled);
     }
 
     LayoutView* m_layoutView;
+    bool m_originalSlimmingPaintEnabled;
 };
 
 class TestDisplayItem : public DisplayItem {