Do not traverse nodes not having a layout object while searching editable visible position.

Source/core/editing/htmlediting.cpp

Index: Source/core/editing/htmlediting.cpp
diff --git a/Source/core/editing/htmlediting.cpp b/Source/core/editing/htmlediting.cpp
index 183a2580a9a40156124e80505bfb7b706f964086..76c226e863634a61b544a50229c96013742d32fc 100644
--- a/Source/core/editing/htmlediting.cpp
+++ b/Source/core/editing/htmlediting.cpp
@@ -355,12 +355,17 @@ PositionInComposedTree nextCandidate(const PositionInComposedTree& position)
 
 Position nextVisuallyDistinctCandidate(const Position& position)
 {
+    // TODO(changseok): Use PositionIterator instead.
     Position p = position;
     Position downstreamStart = p.downstream();
     while (!p.atEndOfTree()) {
         p = p.next(Character);
         if (p.isCandidate() && p.downstream() != downstreamStart)
             return p;
+        if (auto* node = p.containerNode()) {
+            if (!node->layoutObject())
+                p = lastPositionInOrAfterNode(node);
+        }
     }
     return Position();
 }
@@ -391,12 +396,17 @@ PositionInComposedTree previousCandidate(const PositionInComposedTree& position)
 template <typename PositionType>
 PositionType previousVisuallyDistinctCandidateAlgorithm(const PositionType& position)
 {
+    // TODO(changseok): Use PositionIterator instead.
     PositionType p = position;
     PositionType downstreamStart = p.downstream();
     while (!p.atStartOfTree()) {
         p = p.previous(Character);
         if (p.isCandidate() && p.downstream() != downstreamStart)
             return p;
+        if (auto* node = p.containerNode()) {
+            if (!node->layoutObject())
+                p = PositionType::firstPositionInOrBeforeNode(node);
+        }
     }
     return PositionType();
 }