Revert of Revert of Inline sign in extracts gaia id from HTTP header and seeds account tracker

components/signin/core/browser/account_tracker_service.h

Index: components/signin/core/browser/account_tracker_service.h
diff --git a/components/signin/core/browser/account_tracker_service.h b/components/signin/core/browser/account_tracker_service.h
index a6f403e9ea26f4705ac7e753e93a53552ed41da0..c65ed01093408ab87a97703970b25d52234b638f 100644
--- a/components/signin/core/browser/account_tracker_service.h
+++ b/components/signin/core/browser/account_tracker_service.h
@@ -79,6 +79,18 @@
   // there are still unfininshed fetchers.
   virtual bool IsAllUserInfoFetched() const;
 
+  // Picks the correct account_id for the specified account depending on the
+  // migration state.
+  std::string PickAccountIdForAccount(const std::string& gaia,
+                                      const std::string& email);
+  static std::string PickAccountIdForAccount(PrefService* pref_service,
+                                             const std::string& gaia,
+                                             const std::string& email);
+
+  // Seeds the account whose account_id is given by PickAccountIdForAccount()
+  // with its corresponding gaia id and email address.
+  void SeedAccountInfo(const std::string& gaia, const std::string& email);
+
   AccountIdMigrationState GetMigrationState();
   static AccountIdMigrationState GetMigrationState(PrefService* pref_service);