Set needs paint property update when dirtying descendant-dependent properties.

BUG=677239
TEST=See failing tests in 677239 without this change.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2601963002
Cr-Commit-Position: refs/heads/master@{#440889}

third_party/WebKit/Source/core/paint/PaintLayer.cpp

@@ -631,6 +631,9 @@ void PaintLayer::markAncestorChainForDescendantDependentFlagsUpdate() {
     if (layer->m_needsDescendantDependentFlagsUpdate)
       break;
     layer->m_needsDescendantDependentFlagsUpdate = true;
+
+    if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
+      layer->layoutObject()->setNeedsPaintPropertyUpdate();
   }
 }
 
@@ -1012,11 +1015,6 @@ void PaintLayer::setNeedsCompositingInputsUpdate() {
   // dependent flags udpate. Reduce call sites after SPv2 launch allows
   /// removal of CompositingInputsUpdater.
   markAncestorChainForDescendantDependentFlagsUpdate();
-  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
-    // This update is needed in order to re-compute sticky position constraints,
-    // not for any other reason.
-    layoutObject()->setNeedsPaintPropertyUpdate();
-  }
 }
 
 void PaintLayer::setNeedsCompositingInputsUpdateInternal() {