Improve entrance animations on convo page

By moving loading in each controller to the same thread.
There will still be shifting as the conversation prefs are added, but it
won't be the over thte top shift up and shift down motion that existed
prior to this cl.

Test: manual
Fixes: 188734400
Change-Id: I202981b603b8f9308b2b352a0939182910869cd6

src/com/android/settings/notification/app/PriorityConversationsPreferenceController.java

@@ -67,22 +67,9 @@ public class PriorityConversationsPreferenceController extends
     public void updateState(Preference preference) {
         PreferenceCategory pref = (PreferenceCategory) preference;
         // Load conversations
-        new AsyncTask<Void, Void, Void>() {
-            @Override
-            protected Void doInBackground(Void... unused) {
-                mConversations = mBackend.getConversations(true).getList();
-                Collections.sort(mConversations, mConversationComparator);
-                return null;
-            }
-
-            @Override
-            protected void onPostExecute(Void unused) {
-                if (mContext == null) {
-                    return;
-                }
-                populateList(mConversations, pref);
-            }
-        }.execute();
+        mConversations = mBackend.getConversations(true).getList();
+        Collections.sort(mConversations, mConversationComparator);
 
+        populateList(mConversations, pref);
     }
 }