Use Node& instead of Node* as a parameter

there are some functions which node object was passed as a parameter
at child_list_mutation_scope.h. and the object is never nullptr.
so it can be changed to reference instead of pointer.

Bug: 874385
Change-Id: I66f3840c688b50fe622712727e1c3fb0c90bae92
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1604394Reviewed-by: Hayato Ito <hayato@chromium.org>
Commit-Queue: Hwanseung Lee <hs1217.lee@samsung.com>
Cr-Commit-Position: refs/heads/master@{#658994}

third_party/blink/renderer/core/dom/child_list_mutation_scope.cc

@@ -84,45 +84,45 @@ ChildListMutationAccumulator* ChildListMutationAccumulator::GetOrCreate(
   return accumulator;
 }
 
-inline bool ChildListMutationAccumulator::IsAddedNodeInOrder(Node* child) {
-  return IsEmpty() || (last_added_ == child->previousSibling() &&
-                       next_sibling_ == child->nextSibling());
+inline bool ChildListMutationAccumulator::IsAddedNodeInOrder(Node& child) {
+  return IsEmpty() || (last_added_ == child.previousSibling() &&
+                       next_sibling_ == child.nextSibling());
 }
 
-void ChildListMutationAccumulator::ChildAdded(Node* child) {
+void ChildListMutationAccumulator::ChildAdded(Node& child) {
   DCHECK(HasObservers());
 
   if (!IsAddedNodeInOrder(child))
     EnqueueMutationRecord();
 
   if (IsEmpty()) {
-    previous_sibling_ = child->previousSibling();
-    next_sibling_ = child->nextSibling();
+    previous_sibling_ = child.previousSibling();
+    next_sibling_ = child.nextSibling();
   }
 
-  last_added_ = child;
-  added_nodes_.push_back(child);
+  last_added_ = &child;
+  added_nodes_.push_back(&child);
 }
 
-inline bool ChildListMutationAccumulator::IsRemovedNodeInOrder(Node* child) {
-  return IsEmpty() || next_sibling_ == child;
+inline bool ChildListMutationAccumulator::IsRemovedNodeInOrder(Node& child) {
+  return IsEmpty() || next_sibling_ == &child;
 }
 
-void ChildListMutationAccumulator::WillRemoveChild(Node* child) {
+void ChildListMutationAccumulator::WillRemoveChild(Node& child) {
   DCHECK(HasObservers());
 
   if (!added_nodes_.IsEmpty() || !IsRemovedNodeInOrder(child))
     EnqueueMutationRecord();
 
   if (IsEmpty()) {
-    previous_sibling_ = child->previousSibling();
-    next_sibling_ = child->nextSibling();
-    last_added_ = child->previousSibling();
+    previous_sibling_ = child.previousSibling();
+    next_sibling_ = child.nextSibling();
+    last_added_ = child.previousSibling();
   } else {
-    next_sibling_ = child->nextSibling();
+    next_sibling_ = child.nextSibling();
   }
 
-  removed_nodes_.push_back(child);
+  removed_nodes_.push_back(&child);
 }
 
 void ChildListMutationAccumulator::EnqueueMutationRecord() {

third_party/blink/renderer/core/dom/child_list_mutation_scope.h

@@ -56,8 +56,8 @@ class ChildListMutationAccumulator final
 
   ChildListMutationAccumulator(Node*, MutationObserverInterestGroup*);
 
-  void ChildAdded(Node*);
-  void WillRemoveChild(Node*);
+  void ChildAdded(Node&);
+  void WillRemoveChild(Node&);
 
   bool HasObservers() const { return observers_; }
 
@@ -71,8 +71,8 @@ class ChildListMutationAccumulator final
  private:
   void EnqueueMutationRecord();
   bool IsEmpty();
-  bool IsAddedNodeInOrder(Node*);
-  bool IsRemovedNodeInOrder(Node*);
+  bool IsAddedNodeInOrder(Node&);
+  bool IsRemovedNodeInOrder(Node&);
 
   Member<Node> target_;
 
@@ -110,12 +110,12 @@ class ChildListMutationScope final {
 
   void ChildAdded(Node& child) {
     if (accumulator_ && accumulator_->HasObservers())
-      accumulator_->ChildAdded(&child);
+      accumulator_->ChildAdded(child);
   }
 
   void WillRemoveChild(Node& child) {
     if (accumulator_ && accumulator_->HasObservers())
-      accumulator_->WillRemoveChild(&child);
+      accumulator_->WillRemoveChild(child);
   }
 
  private: