Get rid ot unused enum member NGOffsetMappingUnitType::kExpanded

This patch gets rid of unused enum member |NGOffsetMappingUnitType::kExpanded|
for improving code health.

Change-Id: I13331a6974e30e6b7b583be2cee1d1989b003ca0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2167637
Auto-Submit: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762731}

third_party/blink/renderer/core/layout/ng/inline/ng_offset_mapping.cc

@@ -138,7 +138,7 @@ const Node& NGOffsetMappingUnit::GetOwner() const {
 bool NGOffsetMappingUnit::Concatenate(const NGOffsetMappingUnit& other) {
   if (layout_object_ != other.layout_object_)
     return false;
-  if (type_ != other.type_ || type_ == NGOffsetMappingUnitType::kExpanded)
+  if (type_ != other.type_)
     return false;
   if (dom_end_ != other.dom_start_)
     return false;

third_party/blink/renderer/core/layout/ng/inline/ng_offset_mapping.h

@@ -21,7 +21,7 @@ namespace blink {
 class LayoutBlockFlow;
 class LayoutObject;
 
-enum class NGOffsetMappingUnitType { kIdentity, kCollapsed, kExpanded };
+enum class NGOffsetMappingUnitType { kIdentity, kCollapsed };
 
 // An NGOffsetMappingUnit indicates a "simple" offset mapping between dom offset
 // range [dom_start, dom_end] on node |owner| and text content offset range

third_party/blink/renderer/core/layout/ng/inline/ng_offset_mapping_test.cc

@@ -92,7 +92,6 @@ class NGOffsetMappingTest : public NGLayoutTest {
  protected:
   static const auto kCollapsed = NGOffsetMappingUnitType::kCollapsed;
   static const auto kIdentity = NGOffsetMappingUnitType::kIdentity;
-  static const auto kExpanded = NGOffsetMappingUnitType::kExpanded;
 
   void SetUp() override {
     NGLayoutTest::SetUp();