Always load signin profile on Chrome OS startup.

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.cc
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index 08d90f6168176ebb3bbacf25d74de66b5da247e0..93fd0a05fb42b6d224c6231c149418e1df499ea0 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -532,6 +532,12 @@ void ChromeBrowserMainPartsChromeos::PostProfileInit() {
   // -- This used to be in ChromeBrowserMainParts::PreMainMessageLoopRun()
   // -- just after CreateProfile().
 
+  // Force loading of signin profile if it was not loaded before. It is possible
+  // when we are restoring session or skipping login screen for some other
+  // reason.
+  if (!chromeos::ProfileHelper::IsSigninProfile(profile()))

[Nikita (slow), 2015/02/17 14:44:54]

We're discussing with Pavel that another potential optimization here would be
loading "signin profile" in async way since it is not required for session
restore (after crash/just restart) case.

However there's a potential edge case:
* session restore starts
  ** "signin profile" async loading is started
* screen lock is activated which tries to access "signin profile".

+    chromeos::ProfileHelper::GetSigninProfile();
+
   BootTimesRecorder::Get()->OnChromeProcessStart();
 
   // Initialize the network portal detector for Chrome OS. The network