ChromeOS cryptohome should be able to use gaia id as user identifier.

chromeos/dbus/mock_session_manager_client.h

Index: chromeos/dbus/mock_session_manager_client.h
diff --git a/chromeos/dbus/mock_session_manager_client.h b/chromeos/dbus/mock_session_manager_client.h
index aec901a9886982b7231823a71189984176ab13c5..dc7d0956c2b9fa4b0eb4517e43f6e00ae8c71d7c 100644
--- a/chromeos/dbus/mock_session_manager_client.h
+++ b/chromeos/dbus/mock_session_manager_client.h
@@ -7,6 +7,7 @@
 
 #include <string>
 
+#include "chromeos/cryptohome/cryptohome_parameters.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
@@ -25,7 +26,7 @@ class MockSessionManagerClient : public SessionManagerClient {
   MOCK_CONST_METHOD0(IsScreenLocked, bool(void));
   MOCK_METHOD0(EmitLoginPromptVisible, void(void));
   MOCK_METHOD1(RestartJob, void(const std::vector<std::string>&));
-  MOCK_METHOD1(StartSession, void(const std::string&));
+  MOCK_METHOD1(StartSession, void(const cryptohome::Identification&));
   MOCK_METHOD0(StopSession, void(void));
   MOCK_METHOD0(NotifySupervisedUserCreationStarted, void(void));
   MOCK_METHOD0(NotifySupervisedUserCreationFinished, void(void));
@@ -36,9 +37,10 @@ class MockSessionManagerClient : public SessionManagerClient {
   MOCK_METHOD1(RetrieveActiveSessions, void(const ActiveSessionsCallback&));
   MOCK_METHOD1(RetrieveDevicePolicy, void(const RetrievePolicyCallback&));
   MOCK_METHOD2(RetrievePolicyForUser,
-               void(const std::string&,
+               void(const cryptohome::Identification&,
                     const RetrievePolicyCallback&));
-  MOCK_METHOD1(BlockingRetrievePolicyForUser, std::string(const std::string&));
+  MOCK_METHOD1(BlockingRetrievePolicyForUser,
+               std::string(const cryptohome::Identification&));
   MOCK_METHOD2(RetrieveDeviceLocalAccountPolicy,
                void(const std::string&,
                     const RetrievePolicyCallback&));
@@ -46,7 +48,7 @@ class MockSessionManagerClient : public SessionManagerClient {
                void(const std::string&,
                     const StorePolicyCallback&));
   MOCK_METHOD3(StorePolicyForUser,
-               void(const std::string&,
+               void(const cryptohome::Identification&,
                     const std::string&,
                     const StorePolicyCallback&));
   MOCK_METHOD3(StoreDeviceLocalAccountPolicy,
@@ -54,7 +56,7 @@ class MockSessionManagerClient : public SessionManagerClient {
                     const std::string&,
                     const StorePolicyCallback&));
   MOCK_METHOD2(SetFlagsForUser,
-               void(const std::string&,
+               void(const cryptohome::Identification&,
                     const std::vector<std::string>&));
   MOCK_METHOD1(GetServerBackedStateKeys, void(const StateKeysCallback&));
   MOCK_METHOD1(CheckArcAvailability, void(const ArcCallback&));