[DMC #4] Add SingletonMarkerListImpl

third_party/WebKit/Source/core/editing/markers/DocumentMarkerController.cpp

Index: third_party/WebKit/Source/core/editing/markers/DocumentMarkerController.cpp
diff --git a/third_party/WebKit/Source/core/editing/markers/DocumentMarkerController.cpp b/third_party/WebKit/Source/core/editing/markers/DocumentMarkerController.cpp
index cb50ef04b72d7bf4c8da6aca43465502d9f064ad..6d23820cf3904c9669f6223f96cc262e0c30c5eb 100644
--- a/third_party/WebKit/Source/core/editing/markers/DocumentMarkerController.cpp
+++ b/third_party/WebKit/Source/core/editing/markers/DocumentMarkerController.cpp
@@ -37,6 +37,7 @@
 #include "core/editing/markers/DocumentMarkerListEditor.h"
 #include "core/editing/markers/GenericDocumentMarkerListImpl.h"
 #include "core/editing/markers/RenderedDocumentMarker.h"
+#include "core/editing/markers/SingletonMarkerListImpl.h"
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutObject.h"
 
@@ -80,7 +81,12 @@ DocumentMarker::MarkerTypeIndex MarkerTypeToMarkerIndex(
 DocumentMarkerList* CreateListForType(DocumentMarker::MarkerType type) {
   // All MarkerTypes use GenericDocumentMarkerListImpl for now. Eventually we
   // will use different marker list classes for different MarkerTypes.
-  return new GenericDocumentMarkerListImpl();
+  switch (type) {
+    case DocumentMarker::kComposition:
+      return new SingletonMarkerListImpl();
+    default:
+      return new GenericDocumentMarkerListImpl();
+  }
 }
 
 }  // namespace