Make "collapsed" refer only to a thread's replies

The meaning of "collapsed" in the context of a thread was immensely
confusing:

- on a top-level annotation card it referred to whether replies were or
  were not shown
- on a reply, it referred to whether or not the entire annotation was
  hidden

This change removes all reference to the latter meaning. Annotations
(and replies) are still hidden appropriately when searches are
performed, but now collapsing and uncollapsing refers only to the
visibility of the *replies* of the addressed thread.

h/static/scripts/directives/thread.coffee

-### global -COLLAPSED_CLASS ###
-
-COLLAPSED_CLASS = 'thread-collapsed'
-
 ###*
 # @ngdoc type
 # @name thread.ThreadController
@@ -85,10 +81,6 @@ isHiddenThread = (elem) ->
 # @restrict A
 # @description
 # Directive that instantiates {@link thread.ThreadController ThreadController}.
-#
-# If the `thread-collapsed` attribute is specified, it is treated as an
-# expression to watch in the context of the current scope that controls
-# the collapsed state of the thread.
 ###
 thread = [
   '$parse', '$window', 'pulse', 'render',
@@ -136,13 +128,6 @@ thread = [
         event.stopPropagation()
         pulse(elem)
 
-      # Add and remove the collapsed class when the collapsed property changes.
-      scope.$watch (-> ctrl.collapsed), (collapsed) ->
-        if collapsed
-          attrs.$addClass COLLAPSED_CLASS
-        else
-          attrs.$removeClass COLLAPSED_CLASS
-
       # The watch is necessary because the computed value of the attribute
       # expression may change. This won't happen when we use the thread
       # directive in a repeat, since the element will be torn down whenever the
@@ -156,11 +141,6 @@ thread = [
           ctrl.container = thread
           scope.$digest()
 
-      # Watch the thread-collapsed attribute.
-      if attrs.threadCollapsed
-        scope.$watch $parse(attrs.threadCollapsed), (collapsed) ->
-          ctrl.toggleCollapsed(collapsed)
-
     controller: 'ThreadController'
     controllerAs: 'vm'
     link: linkFn

h/static/styles/threads.scss

@@ -20,11 +20,6 @@ $threadexp-width: .6em;
   .thread:first-child {
     margin-top: 0.5em;
   }
-
-  .thread-collapsed {
-    .tag-list, .annotation-body {display: none;}
-    .thread-reply { margin-top: 0 }
-  }
 }
 
 .thread-reply {
@@ -62,14 +57,6 @@ $threadexp-width: .6em;
     border-left: 1px dotted $gray-light;
     padding: 0;
     padding-left: $thread-padding;
-
-    &.thread-collapsed {
-      border-color: transparent;
-
-      & > article markdown {
-        display: none;
-      }
-    }
   }
 
   .threadexp {
@@ -96,19 +83,6 @@ $threadexp-width: .6em;
       }
     }
   }
-
-  &.thread-collapsed {
-    & > ul {
-      display: none;
-    }
-
-    & > .thread-message {
-      .thread &,
-      .thread & .annotation-header,
-      .thread & .annotation-section { margin: 0 }
-      .thread & footer { display: none }
-    }
-  }
 }
 
 .thread-message {

h/templates/client/thread.html

@@ -36,13 +36,12 @@
 </div>
 
 <!-- Replies -->
-<ul class="thread-replies">
+<ul class="thread-replies" ng-hide="vm.collapsed">
   <li class="thread"
       deep-count="count"
       thread="child" thread-filter
       ng-include="'thread.html'"
       ng-init="child.message.id || threadFilter.active(false)"
-      ng-class="{'thread-collapsed': vm.collapsed}"
       ng-repeat="child in vm.container.children
                  | orderBy : 'message.updated' : true"
       ng-show="count('edit') || count('match') || !threadFilter.active()">