Refactor the way PaintArtifactCompositor is attached and used.

third_party/WebKit/Source/core/paint/StubChromeClientForSPv2.h

Index: third_party/WebKit/Source/core/paint/StubChromeClientForSPv2.h
diff --git a/third_party/WebKit/Source/core/paint/StubChromeClientForSPv2.h b/third_party/WebKit/Source/core/paint/StubChromeClientForSPv2.h
index bd979769eee594345e798d02db84a2c2e8d704ed..74c7066a94a3b6868d5a0730d7ce7db7d0b4799d 100644
--- a/third_party/WebKit/Source/core/paint/StubChromeClientForSPv2.h
+++ b/third_party/WebKit/Source/core/paint/StubChromeClientForSPv2.h
@@ -6,7 +6,6 @@
 #define StubChromeClientForSPv2_h
 
 #include "core/loader/EmptyClients.h"
-#include "platform/graphics/compositing/PaintArtifactCompositor.h"
 #include "platform/testing/WebLayerTreeViewImplForTesting.h"
 
 namespace blink {
@@ -16,22 +15,17 @@ namespace blink {
 // simple analysis of the results.
 class StubChromeClientForSPv2 : public EmptyChromeClient {
 public:
-    StubChromeClientForSPv2() : m_layerTreeView()
-    {
-        m_layerTreeView.setRootLayer(*m_paintArtifactCompositor.getWebLayer());
-    }
+    StubChromeClientForSPv2() : m_layerTreeView() { }
 
     bool hasLayer(const WebLayer& layer) { return m_layerTreeView.hasLayer(layer); }
 
-    // ChromeClient
-    void didPaint(const PaintArtifact& artifact) override
+    void attachRootLayer(WebLayer* layer, LocalFrame* localRoot) override
     {
-        m_paintArtifactCompositor.update(artifact);
+        m_layerTreeView.setRootLayer(*layer);
     }
 
 private:
     WebLayerTreeViewImplForTesting m_layerTreeView;
-    PaintArtifactCompositor m_paintArtifactCompositor;
 };
 
 } // namespace blink