Change CanMergeLists() function to take |const Element&| instead of

|Element*| objects.

Bug: 766448
Change-Id: I5c195095cc692f3cc3fd6d7fb68fbaf98ffc875e
Reviewed-on: https://chromium-review.googlesource.com/673146Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Andrey Kraynov <iceman@yandex-team.ru>
Cr-Commit-Position: refs/heads/master@{#504360}

third_party/WebKit/Source/core/editing/EditingUtilities.cpp

@@ -1475,23 +1475,22 @@ static bool IsVisiblyAdjacent(const Position& first, const Position& second) {
              .DeepEquivalent();
 }
 
-bool CanMergeLists(Element* first_list, Element* second_list) {
-  if (!first_list || !second_list || !first_list->IsHTMLElement() ||
-      !second_list->IsHTMLElement())
+bool CanMergeLists(const Element& first_list, const Element& second_list) {
+  if (!first_list.IsHTMLElement() || !second_list.IsHTMLElement())
     return false;
 
-  DCHECK(!NeedsLayoutTreeUpdate(*first_list));
-  DCHECK(!NeedsLayoutTreeUpdate(*second_list));
-  return first_list->HasTagName(
+  DCHECK(!NeedsLayoutTreeUpdate(first_list));
+  DCHECK(!NeedsLayoutTreeUpdate(second_list));
+  return first_list.HasTagName(
              second_list
-                 ->TagQName())  // make sure the list types match (ol vs. ul)
-         && HasEditableStyle(*first_list) &&
-         HasEditableStyle(*second_list)  // both lists are editable
-         && RootEditableElement(*first_list) ==
-                RootEditableElement(
-                    *second_list)  // don't cross editing boundaries
-         && IsVisiblyAdjacent(Position::InParentAfterNode(*first_list),
-                              Position::InParentBeforeNode(*second_list));
+                 .TagQName())  // make sure the list types match (ol vs. ul)
+         && HasEditableStyle(first_list) &&
+         HasEditableStyle(second_list)  // both lists are editable
+         &&
+         RootEditableElement(first_list) ==
+             RootEditableElement(second_list)  // don't cross editing boundaries
+         && IsVisiblyAdjacent(Position::InParentAfterNode(first_list),
+                              Position::InParentBeforeNode(second_list));
   // Make sure there is no visible content between this li and the previous list
 }
 

third_party/WebKit/Source/core/editing/EditingUtilities.h

@@ -367,7 +367,7 @@ HTMLSpanElement* CreateTabSpanElement(Document&, const String& tab_text);
 
 // Boolean functions on Element
 
-bool CanMergeLists(Element* first_list, Element* second_list);
+bool CanMergeLists(const Element& first_list, const Element& second_list);
 
 CORE_EXPORT bool ElementCannotHaveEndTag(const Node&);
 

third_party/WebKit/Source/core/editing/commands/DeleteSelectionCommand.cpp

@@ -68,6 +68,13 @@ static bool IsTableRowEmpty(Node* row) {
   return true;
 }
 
+static bool CanMergeListElements(Element* first_list, Element* second_list) {
+  if (!first_list || !second_list || first_list == second_list)
+    return false;
+
+  return CanMergeLists(*first_list, *second_list);
+}
+
 DeleteSelectionCommand::DeleteSelectionCommand(
     Document& document,
     bool smart_delete,
@@ -877,10 +884,8 @@ void DeleteSelectionCommand::MergeParagraphs(EditingState* editing_state) {
   Node* list_item_in_second_paragraph =
       EnclosingNodeOfType(downstream_end_, IsListItem);
   if (list_item_in_first_paragraph && list_item_in_second_paragraph &&
-      list_item_in_first_paragraph->parentElement() !=
-          list_item_in_second_paragraph->parentElement() &&
-      CanMergeLists(list_item_in_first_paragraph->parentElement(),
-                    list_item_in_second_paragraph->parentElement())) {
+      CanMergeListElements(list_item_in_first_paragraph->parentElement(),
+                           list_item_in_second_paragraph->parentElement())) {
     MergeIdenticalElements(list_item_in_first_paragraph->parentElement(),
                            list_item_in_second_paragraph->parentElement(),
                            editing_state);

third_party/WebKit/Source/core/editing/commands/IndentOutdentCommand.cpp

@@ -134,14 +134,15 @@ bool IndentOutdentCommand::TryIndentingAsListItem(const Position& start,
   }
 
   GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
-  if (CanMergeLists(previous_list, new_list)) {
+  DCHECK(new_list);
+  if (previous_list && CanMergeLists(*previous_list, *new_list)) {
     MergeIdenticalElements(previous_list, new_list, editing_state);
     if (editing_state->IsAborted())
       return false;
   }
 
   GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
-  if (CanMergeLists(new_list, next_list)) {
+  if (next_list && CanMergeLists(*new_list, *next_list)) {
     MergeIdenticalElements(new_list, next_list, editing_state);
     if (editing_state->IsAborted())
       return false;

third_party/WebKit/Source/core/editing/commands/InsertListCommand.cpp

@@ -72,10 +72,11 @@ HTMLUListElement* InsertListCommand::FixOrphanedListChild(
 HTMLElement* InsertListCommand::MergeWithNeighboringLists(
     HTMLElement* passed_list,
     EditingState* editing_state) {
+  DCHECK(passed_list);
   HTMLElement* list = passed_list;
   Element* previous_list = ElementTraversal::PreviousSibling(*list);
   GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
-  if (CanMergeLists(previous_list, list)) {
+  if (previous_list && CanMergeLists(*previous_list, *list)) {
     MergeIdenticalElements(previous_list, list, editing_state);
     if (editing_state->IsAborted())
       return nullptr;
@@ -90,7 +91,7 @@ HTMLElement* InsertListCommand::MergeWithNeighboringLists(
 
   HTMLElement* next_list = ToHTMLElement(next_sibling);
   GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
-  if (CanMergeLists(list, next_list)) {
+  if (CanMergeLists(*list, *next_list)) {
     MergeIdenticalElements(list, next_list, editing_state);
     if (editing_state->IsAborted())
       return nullptr;
@@ -599,7 +600,7 @@ void InsertListCommand::ListifyParagraph(const VisiblePosition& original_start,
       return;
 
     GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
-    if (CanMergeLists(previous_list, next_list))
+    if (previous_list && next_list && CanMergeLists(*previous_list, *next_list))
       MergeIdenticalElements(previous_list, next_list, editing_state);
 
     return;