Deduplicating compositing scrollingCoordinator helper

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 167 matching lines @@
   if (rare_data_ && rare_data_->resource_info) {
     const ComputedStyle& style = GetLayoutObject().StyleRef();
     if (style.HasFilter())
       style.Filter().RemoveClient(rare_data_->resource_info);
     if (IsReferenceClipPath(style.ClipPath())) {
       ToReferenceClipPathOperation(style.ClipPath())
           ->RemoveClient(rare_data_->resource_info);
     }
     rare_data_->resource_info->ClearLayer();
   }
-  if (GetLayoutObject().GetFrame() && GetLayoutObject().GetFrame()->GetPage()) {
-    if (ScrollingCoordinator* scrolling_coordinator =
-            GetLayoutObject().GetFrame()->GetPage()->GetScrollingCoordinator())
+  if (GetLayoutObject().GetFrame()) {
+    if (ScrollingCoordinator* scrolling_coordinator = GetScrollingCoordinator())
       scrolling_coordinator->WillDestroyLayer(this);
   }
 
   if (GroupedMapping()) {
     DisableCompositingQueryAsserts disabler;
     SetGroupedMapping(0, kInvalidateLayerAndRemoveFromMapping);
   }
 
   // Child layers will be deleted by their corresponding layout objects, so
   // we don't need to delete them ourselves.
@@ skipping 2541 matching lines @@
            ((global_paint_flags & kGlobalPaintFlattenCompositingLayers) ||
             GetCompositingState() != kPaintsIntoOwnBacking);
   }
 
   return (Transform() ||
           GetLayoutObject().Style()->GetPosition() == EPosition::kFixed) &&
          ((global_paint_flags & kGlobalPaintFlattenCompositingLayers) ||
           GetCompositingState() != kPaintsIntoOwnBacking);
 }
 
+ScrollingCoordinator* PaintLayer::GetScrollingCoordinator() {
+  Page* page = GetLayoutObject().GetFrame()->GetPage();
+  return (!page) ? nullptr : page->GetScrollingCoordinator();
+}
+
 bool PaintLayer::CompositesWithTransform() const {
   return TransformAncestor() || Transform();
 }
 
 bool PaintLayer::CompositesWithOpacity() const {
   return OpacityAncestor() || GetLayoutObject().Style()->HasOpacity();
 }
 
 bool PaintLayer::BackgroundIsKnownToBeOpaqueInRect(
     const LayoutRect& local_rect) const {
@@ skipping 517 matching lines @@
 }
 
 void showLayerTree(const blink::LayoutObject* layoutObject) {
   if (!layoutObject) {
     LOG(INFO) << "Cannot showLayerTree. Root is (nil)";
     return;
   }
   showLayerTree(layoutObject->EnclosingLayer());
 }
 #endif