Fix assert about lifecycle in setTracksPaintInvalidations for spv2

R=pdr@chromium.org

Review URL: https://codereview.chromium.org/1315543004 .

git-svn-id: svn://svn.chromium.org/blink/trunk@201071 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/layout/compositing/DeprecatedPaintLayerCompositor.cpp

@@ -878,7 +878,9 @@ void DeprecatedPaintLayerCompositor::resetTrackedPaintInvalidationRects()
 
 void DeprecatedPaintLayerCompositor::setTracksPaintInvalidations(bool tracksPaintInvalidations)
 {
-    ASSERT(lifecycle().state() == DocumentLifecycle::PaintInvalidationClean);
+    ASSERT(lifecycle().state() ==
+        (RuntimeEnabledFeatures::slimmingPaintV2Enabled()
+            ? DocumentLifecycle::CompositingForSlimmingPaintV2Clean : DocumentLifecycle::PaintInvalidationClean));
     m_isTrackingPaintInvalidations = tracksPaintInvalidations;
 }