Call process_loaded_for_unread() more directly.

This is a prefactoring to eventually eliminate the home_unread_messages
global variable.  More commits to follow.

In order to set up process_loaded_for_unread() not to modify
global variable to get its job done, we want to pull it out of
add_messages(), so that add_messages() doesn't have to pass back
state to the 9 different places in the codebase where it's called.
There are only 2 places where process_loaded_for_unread() get
called after this commit.

In order to facilitate pulling up process_loaded_for_unread(), I
made it so that the contract for add_messages() was to accept
already-hydrated messages.  This way I could hydrate the messages
before calling process_loaded_for_unread() without have to
worry about double-caching them in add_messages.  This will
slightly improve performance, but it was mostly done for code
clarity.

(imported from commit ad5aaad5b1f22c31647370f4c9dcb5f89d7d99a7)

tools/jslint/check-all.js

@@ -44,6 +44,7 @@ var globals =
     + ' process_visible_unread_messages message_range message_in_table process_loaded_for_unread'
     + ' mark_all_as_read message_unread process_read_messages unread_in_current_view'
     + ' fast_forward_pointer recent_subjects unread_subjects'
+    + ' add_message_metadata'
     ;
 
 

zephyr/static/js/zephyr.js

@@ -662,16 +662,11 @@ function add_messages(messages, msg_list) {
 
     util.destroy_loading_indicator($('#page_loading_indicator'));
     util.destroy_first_run_message();
-    messages = $.map(messages, add_message_metadata);
 
     if (add_messages_helper(messages, msg_list, msg_list.filter.predicate())) {
         prepended = true;
     }
 
-    if (msg_list === all_msg_list) {
-        process_loaded_for_unread(messages);
-    }
-
     if ((msg_list === narrowed_msg_list) && !msg_list.empty() &&
         (msg_list.selected_id() === -1)) {
         // If adding some new messages to the message tables caused
@@ -745,6 +740,7 @@ function maybe_add_narrowed_messages(messages, msg_list) {
                 }
             });
 
+            new_messages = $.map(new_messages, add_message_metadata);
             add_messages(new_messages, msg_list);
             process_visible_unread_messages();
             compose.update_faded_messages();
@@ -848,13 +844,13 @@ function get_updates(options) {
                 // server update.  Once that bug is fixed, this
                 // should no longer be needed
                 messages = deduplicate_messages(messages);
+                messages = $.map(messages, add_message_metadata);
 
-                // Our unread counts infrastructure (which runs when
+                // You must add add messages to home_msg_list BEFORE
-                // we add messages to all_msg_list) expects
+                // calling process_loaded_for_unread.
-                // add_messages to have already been called since
-                // update_unread_counts checks whether message are in
-                // the home view.
                 add_messages(messages, home_msg_list);
+                process_loaded_for_unread(messages);
+
                 add_messages(messages, all_msg_list);
 
                 if (narrow.active()) {
@@ -940,10 +936,13 @@ function load_old_messages(opts) {
             narrow.show_empty_narrow_message();
         }
 
+        messages = $.map(messages, add_message_metadata);
+
         // If we're loading more messages into the home view, save them to
         // the all_msg_list as well, as the home_msg_list is reconstructed
         // from all_msg_list.
         if (opts.msg_list === home_msg_list) {
+            process_loaded_for_unread(messages);
             add_messages(messages, all_msg_list);
         }