UX: improve handling of PM drafts

- Show PM draft if it exists on any of the your user tabs
- If a draft is already open when visiting user profile suppress loading of draft

app/assets/javascripts/discourse/controllers/composer.js.es6

@@ -473,6 +473,12 @@ export default Ember.Controller.extend({
       alert("composer was opened without a draft key");
       throw "composer opened without a proper draft key";
     }
+    const self = this;
+    let composerModel = this.get('model');
+
+    if (opts.ignoreIfChanged && composerModel && composerModel.composeState !== Composer.CLOSED) {
+      return;
+    }
 
     // If we show the subcategory list, scope the categories drop down to
     // the category we opened the composer with.
@@ -480,8 +486,6 @@ export default Ember.Controller.extend({
       this.set('scopedCategoryId', opts.categoryId);
     }
 
-    const self = this;
-    let composerModel = this.get('model');
 
     this.setProperties({ showEditReason: false, editReason: null });
 

app/assets/javascripts/discourse/routes/user-private-messages.js.es6

@@ -1,5 +1,3 @@
-import Draft from 'discourse/models/draft';
-
 export default Discourse.Route.extend({
 
   renderTemplate() {
@@ -11,25 +9,6 @@ export default Discourse.Route.extend({
     return this.modelFor("user");
   },
 
-  setupController(controller, user) {
-    this._super();
-    // Bring up a draft
-    const composerController = this.controllerFor("composer");
-    controller.set("model", user);
-    if (this.currentUser) {
-      Draft.get("new_private_message").then(function(data) {
-        if (data.draft) {
-          composerController.open({
-            draft: data.draft,
-            draftKey: "new_private_message",
-            ignoreIfChanged: true,
-            draftSequence: data.draft_sequence
-          });
-        }
-      });
-    }
-  },
-
   actions: {
     willTransition: function() {
       this._super();

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

@@ -1,5 +1,7 @@
 const INDEX_STREAM_ROUTES = ["user.deletedPosts", "user.flaggedPosts", "userActivity.index"];
 
+import Draft from 'discourse/models/draft';
+
 export default Discourse.Route.extend({
 
   titleToken() {
@@ -55,6 +57,21 @@ export default Discourse.Route.extend({
   setupController(controller, user) {
     controller.set('model', user);
     this.searchService.set('searchContext', user.get('searchContext'));
+
+    const composerController = this.controllerFor("composer");
+    controller.set("model", user);
+    if (this.currentUser) {
+      Draft.get("new_private_message").then(function(data) {
+        if (data.draft) {
+          composerController.open({
+            draft: data.draft,
+            draftKey: "new_private_message",
+            ignoreIfChanged: true,
+            draftSequence: data.draft_sequence
+          });
+        }
+      });
+    }
   },
 
   activate() {