Get rid of .underlayer

/cc: @nathansobo

src/highlights-component.coffee

@@ -12,11 +12,6 @@ class HighlightsComponent
     @domNode = document.createElement('div')
     @domNode.classList.add('highlights')
 
-    if atom.config.get('editor.useShadowDOM')
-      insertionPoint = document.createElement('content')
-      insertionPoint.setAttribute('select', '.underlayer')
-      @domNode.appendChild(insertionPoint)
-
   getDomNode: ->
     @domNode
 

static/text-editor-light.less

@@ -100,15 +100,6 @@ atom-text-editor {
     min-width: 0;
   }
 
-  .underlayer {
-    position: absolute;
-    z-index: -2;
-    top: 0;
-    bottom: 0;
-    left: 0;
-    right: 0;
-  }
-
   .highlight {
     background: none;
     padding: 0;

static/text-editor-shadow.less

@@ -81,15 +81,6 @@
   min-width: 0;
 }
 
-.underlayer {
-  position: absolute;
-  z-index: -2;
-  top: 0;
-  bottom: 0;
-  left: 0;
-  right: 0;
-}
-
 .highlight {
   background: none;
   padding: 0;