Use 'match' instead of 'hits'.

The threadFilter only needs to be tracking the single message in
the container. It is the deepCount that aggregates the results.
There's no longer any reason to cache a __filterResult.

h/static/scripts/directives/threadFilter.coffee

@@ -2,7 +2,7 @@
 # @ngdoc type
 # @name threadFilter.ThreadFilterController
 #
-# @property {Object} hits The number of messages that match the filters.
+# @property {boolean} match True if the last checked message was a match.
 #
 # @description
 # `ThreadFilterController` provides an API for maintaining filtering over
@@ -11,7 +11,7 @@
 ThreadFilterController = [
   'viewFilter'
   (viewFilter) ->
-    @hits = 0
+    @match = false
 
     @_active = false
     @_children = []
@@ -86,18 +86,14 @@ ThreadFilterController = [
     # @description
     # Check whether a message container carries a message matching the
     # configured filters. If filtering is not active then the result is
-    # always `true`.  Updates the `hits` property to reflect changes in match
-    # status of the container by caching the result is the `__filterResult`
-    # property of the container.
+    # always `true`. Updates the `match` property to reflect the result.
     ###
     this.check = (container) ->
       unless container?.message then return false
       if this.active()
-        match = !!viewFilter.filter([container.message], @_filters).length
+        @match = !!viewFilter.filter([container.message], @_filters).length
       else
-        match = true
-      @hits += (match - !!container.__filterResult)
-      container.__filterResult = match
+        @match = true
 
     ###*
     # @ngdoc method
@@ -141,19 +137,22 @@ ThreadFilterController = [
 # The threadFilter directive utilizes the {@link searchfilter searchfilter}
 # service to parse the expression passed in the directive attribute as a
 # faceted search query and configures its controller with the resulting
-# filters. It watches the `hits` property of the controller and updates
+# filters. It watches the `match` property of the controller and updates
 # its thread's message count under the 'filter' key.
 ###
 threadFilter = [
   '$parse', 'searchfilter'
   ($parse,   searchfilter) ->
     linkFn = (scope, elem, attrs, [ctrl, thread, counter]) ->
-      scope.$watch (-> ctrl.hits), (newValue=0, oldValue=0) ->
-        counter?.count 'match', newValue - oldValue
+      if counter?
+        scope.$watch (-> ctrl.match), (match, old) ->
+          if match and not old
+            counter.count 'match', 1
+          else if old
+            counter.count 'match', -1
 
-      scope.$on '$destroy', ->
-        if thread.container then delete thread.container.__filterResult
-        counter?.count 'match', -ctrl.hits
+        scope.$on '$destroy', ->
+          if ctrl.match then counter.count 'match', -1
 
       if parentCtrl = elem.parent().controller('threadFilter')
         ctrl.filters parentCtrl.filters()