Use ContainerNode& instead of ContainerNode* as a parameter

When RemovedFrom called, ContainerNode object was passed as a parameter.
and it is never nullptr. so it can be changed to reference instead of pointer.

Bug: 874385
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I231b13529f83540c7ad64d023d7421bc7a3f8ef6
Reviewed-on: https://chromium-review.googlesource.com/1215142Reviewed-by: Hayato Ito <hayato@chromium.org>
Commit-Queue: Hwanseung Lee <hs1217.lee@samsung.com>
Cr-Commit-Position: refs/heads/master@{#589827}

third_party/blink/renderer/core/css/style_element.cc

@@ -75,14 +75,14 @@ StyleElement::ProcessingResult StyleElement::ProcessStyleSheet(
 }
 
 void StyleElement::RemovedFrom(Element& element,
-                               ContainerNode* insertion_point) {
-  if (!insertion_point->isConnected())
+                               ContainerNode& insertion_point) {
+  if (!insertion_point.isConnected())
     return;
 
   Document& document = element.GetDocument();
   if (registered_as_candidate_) {
     document.GetStyleEngine().RemoveStyleSheetCandidateNode(element,
-                                                            *insertion_point);
+                                                            insertion_point);
     registered_as_candidate_ = false;
   }
 

third_party/blink/renderer/core/css/style_element.h

@@ -49,7 +49,7 @@ class CORE_EXPORT StyleElement : public GarbageCollectedMixin {
   bool SheetLoaded(Document&);
   void StartLoadingDynamicSheet(Document&);
 
-  void RemovedFrom(Element&, ContainerNode* insertion_point);
+  void RemovedFrom(Element&, ContainerNode& insertion_point);
   ProcessingResult ProcessStyleSheet(Document&, Element&);
   ProcessingResult ChildrenChanged(Element&);
   ProcessingResult FinishParsingChildren(Element&);

third_party/blink/renderer/core/html/html_style_element.cc

@@ -89,7 +89,7 @@ Node::InsertionNotificationRequest HTMLStyleElement::InsertedInto(
 
 void HTMLStyleElement::RemovedFrom(ContainerNode& insertion_point) {
   HTMLElement::RemovedFrom(insertion_point);
-  StyleElement::RemovedFrom(*this, &insertion_point);
+  StyleElement::RemovedFrom(*this, insertion_point);
 }
 
 void HTMLStyleElement::ChildrenChanged(const ChildrenChange& change) {

third_party/blink/renderer/core/svg/svg_style_element.cc

@@ -117,7 +117,7 @@ Node::InsertionNotificationRequest SVGStyleElement::InsertedInto(
 
 void SVGStyleElement::RemovedFrom(ContainerNode& insertion_point) {
   SVGElement::RemovedFrom(insertion_point);
-  StyleElement::RemovedFrom(*this, &insertion_point);
+  StyleElement::RemovedFrom(*this, insertion_point);
 }
 
 void SVGStyleElement::ChildrenChanged(const ChildrenChange& change) {