Add new private message button on topics list

That'll teach me to wildly refactor things.

app/assets/javascripts/discourse/controllers/user-topics-list.js.es6

@@ -1,7 +1,7 @@
 import ObjectController from 'discourse/controllers/object';
 
 // Lists of topics on a user's page.
-export default ObjectController.extend({
+export default ObjectController.extend(Discourse.HasCurrentUser, {
   needs: ["application"],
   hideCategory: false,
   showParticipants: false,

app/assets/javascripts/discourse/routes/user.js.es6

@@ -15,11 +15,11 @@ export default Discourse.Route.extend({
       Discourse.logout();
     },
 
-    composePrivateMessage: function() {
-      var user = this.modelFor('user');
+    composePrivateMessage: function(user) {
+      var recipient = user ? user.username : '';
       return this.controllerFor('composer').open({
         action: Discourse.Composer.PRIVATE_MESSAGE,
-        usernames: user.get('username'),
+        usernames: recipient,
         archetypeId: 'private_message',
         draftKey: 'new_private_message'
       });

app/assets/javascripts/discourse/templates/list/user_topics_list.hbs

@@ -1,3 +1,9 @@
+{{#if currentUser.can_send_private_messages}}
+  <div class="clearfix">
+    <a class='btn btn-primary pull-right new-private-message' {{action "composePrivateMessage"}}>{{fa-icon "envelope"}}{{i18n user.new_private_message}}</a>
+  </div>
+{{/if}}
+
 {{basic-topic-list topicList=model
                    hideCategory=hideCategory
                    showParticipants=showParticipants

app/assets/stylesheets/common/base/user.scss

@@ -73,3 +73,6 @@
   }
 }
 
+.new-private-message {
+  margin-bottom: 15px;
+}

app/serializers/user_serializer.rb

@@ -45,6 +45,7 @@ class UserSerializer < BasicUserSerializer
              :can_edit_email,
              :can_edit_name,
              :stats,
+             :can_send_private_messages,
              :can_send_private_message_to_user,
              :bio_excerpt,
              :trust_level,
@@ -178,6 +179,12 @@ class UserSerializer < BasicUserSerializer
     UserAction.stats(object.id, scope)
   end
 
+  # Needed because 'send_private_message_to_user' will always return false
+  # when the current user is being serialized
+  def can_send_private_messages
+    scope.can_send_private_message?(Discourse.system_user)
+  end
+
   def can_send_private_message_to_user
     scope.can_send_private_message?(object)
   end

config/locales/client.en.yml

@@ -293,6 +293,7 @@ en:
       mute: "Mute"
       edit: "Edit Preferences"
       download_archive: "download archive of my posts"
+      new_private_message: "New Private Message"
       private_message: "Private Message"
       private_messages: "Messages"
       activity_stream: "Activity"