Move needsPreviewElement to TimelineUIUtilsImple and make it private

Source/devtools/front_end/timeline/TimelineUIUtils.js

Index: Source/devtools/front_end/timeline/TimelineUIUtils.js
diff --git a/Source/devtools/front_end/timeline/TimelineUIUtils.js b/Source/devtools/front_end/timeline/TimelineUIUtils.js
index f264de7410ef45d7cd451ad6d34d033d09d83b36..6fa2a41ec833030b5eef670b34d2d614ac1c3db1 100644
--- a/Source/devtools/front_end/timeline/TimelineUIUtils.js
+++ b/Source/devtools/front_end/timeline/TimelineUIUtils.js
@@ -213,26 +213,6 @@ WebInspector.TimelineUIUtils.recordStyle = function(record)
 }
 
 /**
- * @param {string=} recordType
- * @return {boolean}
- */
-WebInspector.TimelineUIUtils.needsPreviewElement = function(recordType)
-{
-    if (!recordType)
-        return false;
-    const recordTypes = WebInspector.TimelineModel.RecordType;
-    switch (recordType) {
-    case recordTypes.ResourceSendRequest:
-    case recordTypes.ResourceReceiveResponse:
-    case recordTypes.ResourceReceivedData:
-    case recordTypes.ResourceFinish:
-        return true;
-    default:
-        return false;
-    }
-}
-
-/**
  * @param {!WebInspector.TimelineModel} model
  * @param {!{name: string, tasks: !Array.<!{startTime: number, endTime: number}>, firstTaskIndex: number, lastTaskIndex: number}} info
  * @return {!Element}