GuestSessionRlzTest: Wait for InitRlzImpl finish

Test was checking the brand while initializer was in CollectRlzParams
function. Added a closure to wait until InitRlzImpl is finished.

Bug: 997360
Change-Id: I23af618472396b660b82b3f4ed76fa50fb45d879
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2113473Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752547}

chrome/browser/chromeos/login/session/chrome_session_manager_browsertest.cc

@@ -289,8 +289,11 @@ class GuestSessionRlzTest : public InProcessBrowserTest,
   DISALLOW_COPY_AND_ASSIGN(GuestSessionRlzTest);
 };
 
-// Flaky. https://crbug.com/997360.
-IN_PROC_BROWSER_TEST_P(GuestSessionRlzTest, DISABLED_DeviceIsLocked) {
+IN_PROC_BROWSER_TEST_P(GuestSessionRlzTest, DeviceIsLocked) {
+  base::RunLoop loop;
+  UserSessionInitializer::Get()->set_init_rlz_impl_closure_for_testing(
+      loop.QuitClosure());
+  loop.Run();
   const char* const expected_brand =
       stub_install_attributes()->IsDeviceLocked() ? "TEST" : "";
   EXPECT_EQ(expected_brand, google_brand::chromeos::GetBrand());

chrome/browser/chromeos/login/session/user_session_initializer.cc

@@ -240,6 +240,8 @@ void UserSessionInitializer::InitRlzImpl(Profile* profile,
       ChromeRLZTrackerDelegate::IsGoogleHomepage(profile),
       ChromeRLZTrackerDelegate::IsGoogleInStartpages(profile));
 #endif
+  if (init_rlz_impl_closure_for_testing_)
+    std::move(init_rlz_impl_closure_for_testing_).Run();
 }
 
 }  // namespace chromeos

chrome/browser/chromeos/login/session/user_session_initializer.h

@@ -44,6 +44,10 @@ class UserSessionInitializer : public session_manager::SessionManagerObserver {
   // Initialize child user profile services that depend on the policy.
   void InitializeChildUserServices(Profile* profile);
 
+  void set_init_rlz_impl_closure_for_testing(base::OnceClosure closure) {
+    init_rlz_impl_closure_for_testing_ = std::move(closure);
+  }
+
  private:
   // Initialize RLZ.
   void InitRlz(Profile* profile);
@@ -66,6 +70,8 @@ class UserSessionInitializer : public session_manager::SessionManagerObserver {
   // Initializes RLZ. If |disabled| is true, RLZ pings are disabled.
   void InitRlzImpl(Profile* profile, const RlzInitParams& params);
 
+  base::OnceClosure init_rlz_impl_closure_for_testing_;
+
   base::WeakPtrFactory<UserSessionInitializer> weak_factory_{this};
 };