Bug 1811412 - Move mail-startup-done until after the first about:3pane page loads. r=aleca

Differential Revision: https://phabricator.services.mozilla.com/D167345

--HG--
extra : rebase_source : 53e133aeb0c8545b116dfccf470c7057e23a90d7
extra : amend_source : d03d6df8c31964be4aaad201786354bedb16bb0a
extra : histedit_source : db91e19e34c5adfb591920ebb9179c8063f5f432%2Ca1638ee9e1feca64d4bbda650432d4a6a3f9d15a

mail/base/content/mailTabs.js

@@ -89,6 +89,13 @@ var newMailTabType = {
               tab.messagePaneVisible
             );
           }
+
+          // The first tab has loaded and ready for the user to interact with
+          // it. We can let the rest of the start-up happen now without
+          // appearing to slow the program down.
+          if (tab.first) {
+            Services.obs.notifyObservers(window, "mail-startup-done");
+          }
         });
 
         // `browser` and `linkedBrowser` refer to the message display browser

mail/base/content/messenger.js

@@ -430,11 +430,6 @@ var gMailInit = {
       gSpacesToolbar.onLoad();
     }
 
-    // All core modal dialogs are done, the user can now interact with the
-    // 3-pane window. We need to notify this even if the user didn't setup any
-    // mail account in order to trigger all the other areas of the application.
-    Services.obs.notifyObservers(window, "mail-startup-done");
-
     // Show the end of year donation appeal page.
     if (this.shouldShowEOYDonationAppeal()) {
       // Add a timeout to prevent opening the browser immediately at startup.

mail/base/test/performance/browser_startup.js

@@ -71,9 +71,11 @@ const startupPhases = {
     denylist: {
       modules: new Set([
         "chrome://openpgp/content/BondOpenPGP.jsm",
+        "chrome://openpgp/content/modules/core.jsm",
         "resource:///modules/index_im.sys.mjs",
         "resource:///modules/MsgDBCacheManager.jsm",
         "resource:///modules/PeriodicFilterManager.jsm",
+        "resource://gre/modules/Blocklist.jsm",
         "resource://gre/modules/NewTabUtils.sys.mjs",
         "resource://gre/modules/Sqlite.sys.mjs",
         // Bug 1660907: These core modules shouldn't really be being loaded
@@ -95,7 +97,6 @@ const startupPhases = {
   "before handling user events": {
     denylist: {
       modules: new Set([
-        "chrome://openpgp/content/modules/core.jsm",
         "resource:///modules/gloda/Everybody.jsm",
         "resource:///modules/gloda/Gloda.jsm",
         "resource:///modules/gloda/GlodaContent.jsm",
@@ -117,7 +118,6 @@ const startupPhases = {
         "resource:///modules/jsmime.jsm",
         "resource:///modules/MimeJSComponents.jsm",
         "resource:///modules/mimeParser.jsm",
-        "resource://gre/modules/Blocklist.jsm",
         "resource://gre/modules/BookmarkHTMLUtils.sys.mjs",
         "resource://gre/modules/Bookmarks.sys.mjs",
         "resource://gre/modules/ContextualIdentityService.jsm",