Always load signin profile on Chrome OS startup.

chrome/browser/profiles/profile_browsertest.cc

Index: chrome/browser/profiles/profile_browsertest.cc
diff --git a/chrome/browser/profiles/profile_browsertest.cc b/chrome/browser/profiles/profile_browsertest.cc
index ec06bd71929fa705944f306865d3a136a5c72fd7..421835508d9827c5b5eb7e2eb8475bd6ba57e6f3 100644
--- a/chrome/browser/profiles/profile_browsertest.cc
+++ b/chrome/browser/profiles/profile_browsertest.cc
@@ -15,6 +15,7 @@
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/profiles/chrome_version_service.h"
 #include "chrome/browser/profiles/profile_impl.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -359,6 +360,14 @@ IN_PROC_BROWSER_TEST_F(ProfileBrowserTest,
   ASSERT_NE(loaded_profiles.size(), 0UL);
   Profile* profile = loaded_profiles[0];
 
+#if defined(OS_CHROMEOS)
+  for (const auto& loaded_profile : loaded_profiles) {
+    if (!chromeos::ProfileHelper::IsSigninProfile(loaded_profile)) {
+      profile = loaded_profile;
+    }
+  }
+#endif
+
   // This retry loop reduces flakiness due to the fact that this ultimately
   // tests whether or not a code path hits a timed wait.
   bool succeeded = false;