Simplify setVisibleHighlights function

setVisibleHighlights was previously two methods disguised as one, behind
the "notify" parameter. This commit moves all the code related to
actually changing local state into the onSetVisibleHighlights handler,
making the setVisibleHighlights function responsible solely for firing
the event.

h/static/scripts/guest.coffee

@@ -188,7 +188,6 @@ class Annotator.Guest extends Annotator
     )
 
     .bind('setVisibleHighlights', (ctx, state) =>
-      this.setVisibleHighlights state, false
       this.publish 'setVisibleHighlights', state
     )
 
@@ -315,17 +314,10 @@ class Annotator.Guest extends Annotator
       method: 'setTool'
       params: name
 
-  setVisibleHighlights: (state=true, notify=true) ->
-    if notify
-      @panel?.notify
-        method: 'setVisibleHighlights'
-        params: state
-    else
-      markerClass = 'annotator-highlights-always-on'
-      if state or this.tool is 'highlight'
-        @element.addClass markerClass
-      else
-        @element.removeClass markerClass
+  setVisibleHighlights: (state) ->
+    @panel?.notify
+      method: 'setVisibleHighlights'
+      params: state
 
   addComment: ->
     this.showEditor(this.createAnnotation())
@@ -360,10 +352,14 @@ class Annotator.Guest extends Annotator
   onSetTool: (name) ->
     switch name
       when 'comment'
-        this.setVisibleHighlights this.visibleHighlights, false
+        this.setVisibleHighlights this.visibleHighlights
       when 'highlight'
-        this.setVisibleHighlights true, false
+        this.setVisibleHighlights true
 
-  onSetVisibleHighlights: (state) =>
+  onSetVisibleHighlights: (state) ->
+    markerClass = 'annotator-highlights-always-on'
+    if state or this.tool is 'highlight'
+      @element.addClass markerClass
+    else
+      @element.removeClass markerClass
     this.visibleHighlights = state
-    this.setVisibleHighlights state, false