Refactor LayoutTreeBuilderTraversal to expose a cleaner interface to layout sibling nodes.

third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.h

Index: third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.h
diff --git a/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.h b/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.h
index 2d88e1685fd12977a6373b35d83c5b6b12e15b92..a5d2283846b61006f973e517245218a9489db4ba 100644
--- a/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.h
+++ b/third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.h
@@ -37,6 +37,9 @@ namespace blink {
 class LayoutObject;
 
 class CORE_EXPORT LayoutTreeBuilderTraversal {
+  static Node* nextLayoutSibling(const Node&, int32_t& limit);
+  static Node* previousLayoutSibling(const Node&, int32_t& limit);

[rune, 2017/03/10 12:32:41]

I'd put these in a private section below the public section instead. Or since
these are private, couldn't they be static functions in the cpp file instead,
like we do with other methods?

Oh, you're using it below. Will it be a perf-issue if you implement
nextLayoutSibling() in the cpp file instead? I'd guess that the compiler would
inline a static nextLayoutSibling function into that implementation.

+
  public:
   static const int32_t kTraverseAllSiblings = -2;
   class ParentDetails {
@@ -61,6 +64,14 @@ class CORE_EXPORT LayoutTreeBuilderTraversal {
   static ContainerNode* layoutParent(const Node&, ParentDetails* = nullptr);
   static Node* firstChild(const Node&);
   static Node* nextSibling(const Node&);
+  static Node* nextLayoutSibling(const Node& node) {
+    int32_t limit = kTraverseAllSiblings;
+    return nextLayoutSibling(node, limit);
+  }
+  static Node* previousLayoutSibling(const Node& node) {
+    int32_t limit = kTraverseAllSiblings;
+    return previousLayoutSibling(node, limit);
+  }
   static Node* previousSibling(const Node&);
   static Node* previous(const Node&, const Node* stayWithin);
   static Node* next(const Node&, const Node* stayWithin);