[REF] mail: clean some JS code

1. Removed `getLocalMessages` method in mailbox, and replaced
   with an override on `getMessages`.

   (This method was used before the distinction was made
   between `getMessages` and `fetchMessages`)

2. Removed unused method `_warnUpdatedUnreadCounter` in
   abstract thread window.

   (Leftover from an early POC)

3. Set the default value `''` for the status of a thread.

   (The method `getStatus` should always return a string)

4. Enforce default value `false` for detached status of channel.

   (The method `isDetached` should always return a boolean)

5. Improve readability of some tests.

   (removed useless variables and/or redundant code)

1 files changed, 11 insertions, 9 deletions

diff --git a/addons/mail/static/src/js/thread_windows/thread_window.js b/addons/mail/static/src/js/thread_windows/thread_window.js
index f0662b531b9..20c0965205e 100644
--- a/addons/mail/static/src/js/thread_windows/thread_window.js
+++ b/addons/mail/static/src/js/thread_windows/thread_window.js
@@ -157,14 +157,6 @@ var ThreadWindow = AbstractThreadWindow.extend({
         this._passive = false;
     },
     /**
-     * Set the thread window in passive mode, so that new received message will
-     * keep the thread window as unread until there is focus on the thread
-     * window.
-     */
-    setPassive: function () {
-        this._passive = true;
-    },
-    /**
      * Update this thread window
      *
      * @param {Object} options
@@ -177,7 +169,7 @@ var ThreadWindow = AbstractThreadWindow.extend({
     update: function (options) {
         var self = this;
         if (options.passively) {
-            this.setPassive();
+            this._setPassive();
         }
         var bottomVisible = !this.isFolded() &&
                             !this.isHidden() &&
@@ -232,6 +224,16 @@ var ThreadWindow = AbstractThreadWindow.extend({
         this.call('mail_service', 'openThreadWindow', this.getID());
     },
     /**
+     * Set the thread window in passive mode, so that new received message will
+     * keep the thread window as unread until there is focus on the thread
+     * window.
+     *
+     * @private
+     */
+    _setPassive: function () {
+        this._passive = true;
+    },
+    /**
      * @private
      */
     _startWithoutThread: function () {