Add EditingMarkerList in preparation for DocumentMarkerController refactor

third_party/WebKit/Source/core/editing/BUILD.gn

Index: third_party/WebKit/Source/core/editing/BUILD.gn
diff --git a/third_party/WebKit/Source/core/editing/BUILD.gn b/third_party/WebKit/Source/core/editing/BUILD.gn
index 6bd064919ec3c6f52eea709ef19d62c714bdac01..fca8b818e7681daea128f60a9ca74f8323cf9764 100644
--- a/third_party/WebKit/Source/core/editing/BUILD.gn
+++ b/third_party/WebKit/Source/core/editing/BUILD.gn
@@ -193,6 +193,8 @@ blink_core_sources("editing") {
     "markers/DocumentMarkerController.h",
     "markers/DocumentMarkerList.cpp",
     "markers/DocumentMarkerList.h",
+    "markers/EditingMarkerList.cpp",
+    "markers/EditingMarkerList.h",
     "markers/RenderedDocumentMarker.cpp",
     "markers/RenderedDocumentMarker.h",
     "serializers/HTMLInterchange.cpp",
@@ -290,6 +292,7 @@ source_set("unit_tests") {
     "markers/DocumentMarkerControllerTest.cpp",
     "markers/DocumentMarkerListTest.cpp",
     "markers/DocumentMarkerTest.cpp",
+    "markers/EditingMarkerListTest.cpp",
     "serializers/StyledMarkupSerializerTest.cpp",
     "spellcheck/IdleSpellCheckCallbackTest.cpp",
     "spellcheck/SpellCheckTestBase.cpp",