Simplify the render service

After I changed it so that it took a callback rather than a scope
the data parameter became rather useless.

h/static/scripts/directives/thread.coffee

@@ -85,8 +85,8 @@ ThreadController = [
     $element.hide()
 
     # Render the view in a future animation frame
-    render $parse($attrs.thread)($scope), (value) ->
-      vm.container = value
+    render ->
+      vm.container = $parse($attrs.thread)($scope)
       $scope.$digest()
       $element.show()
 

h/static/scripts/services.coffee

-# The render function accepts a scope and a data object and schedule the scope
-# to be updated with the provided data and digested before the next repaint
-# using window.requestAnimationFrame() (or a fallback). If the resulting digest
-# causes a subsequent invocation of the render function the digest rate is
-# effectively limited to ensure a responsive user interface.
+# The render service is a function wrapper for scheduling sequential updates
+# on window.requestAnimationFrame(). Invoke the function with a callback that
+# and the callback will be queued. One callback is handled per animation frame.
+# Use this service to schedule DOM-intensive digests.
 renderFactory = ['$$rAF', ($$rAF) ->
   renderFrame = null
   renderQueue = []
 
   render = ->
     return renderFrame = null if renderQueue.length is 0
-    {data, cb} = renderQueue.shift()
+    do renderQueue.shift()
     $$rAF(render)
-    cb(data)
 
-  (data, cb) ->
-    renderQueue.push {data, cb}
+  (cb) ->
+    renderQueue.push cb
     renderFrame = $$rAF(render) unless renderFrame
 ]
 

tests/js/directives/thread-test.coffee

@@ -18,7 +18,7 @@ describe 'h.directives.thread', ->
       thread: 'thread'
     $scope = $rootScope.$new()
     flash = sinon.spy()
-    render = (value, cb) -> cb(value)
+    render = (cb) -> cb()
 
     createController = ->
       $scope.thread = mail.messageContainer()