chromeos: adds option for TestSessionControllerClient not to use lower-case

I'm converting some tests, and would like to avoid having to update a bunch
of places to use lower case strings.

BUG=756085
TEST=none

Change-Id: I4beba5088736a6f1c9dbf040741073ce19016097
Reviewed-on: https://chromium-review.googlesource.com/c/1329930Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606986}

ash/session/test_session_controller_client.cc

@@ -139,7 +139,9 @@ void TestSessionControllerClient::AddUserSession(
     bool provide_pref_service,
     bool is_new_profile,
     const std::string& service_user_id) {
-  auto account_id = AccountId::FromUserEmail(GetUserIdFromEmail(display_email));
+  auto account_id = AccountId::FromUserEmail(
+      use_lower_case_user_id_ ? GetUserIdFromEmail(display_email)
+                              : display_email);
   mojom::UserSessionPtr session = mojom::UserSession::New();
   session->session_id = ++fake_session_id_;
   session->user_info = mojom::UserInfo::New();

ash/session/test_session_controller_client.h

@@ -41,6 +41,10 @@ class TestSessionControllerClient : public ash::mojom::SessionControllerClient {
   // Sets up the default state of SessionController.
   void Reset();
 
+  void set_use_lower_case_user_id(bool value) {
+    use_lower_case_user_id_ = value;
+  }
+
   // Helpers to set SessionController state.
   void SetCanLockScreen(bool can_lock);
   void SetShouldLockScreenAutomatically(bool should_lock);
@@ -92,6 +96,8 @@ class TestSessionControllerClient : public ash::mojom::SessionControllerClient {
   int fake_session_id_ = 0;
   mojom::SessionInfoPtr session_info_;
 
+  bool use_lower_case_user_id_ = true;
+
   DISALLOW_COPY_AND_ASSIGN(TestSessionControllerClient);
 };