Add an API to expose results of Account Manager migrations

Chrome OS Account Manager migrator currently does not expose the results
of its migration runs. Add a
|AccountManagerMigrator::GetLastMigrationRunResult|.

This will be used to retry migrations in ARC.

Bug: 998111
Change-Id: I528c9fe04d144d3c883aebc45f1cd30da1e52bdb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1773218Reviewed-by: Alexander Hendrich <hendrich@chromium.org>
Commit-Queue: Kush Sinha <sinhak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690780}

chrome/browser/chromeos/account_manager/account_manager_migrator.cc

@@ -567,6 +567,11 @@ AccountMigrationRunner::Status AccountManagerMigrator::GetStatus() const {
   return migration_runner_.GetStatus();
 }
 
+base::Optional<AccountMigrationRunner::MigrationResult>
+AccountManagerMigrator::GetLastMigrationRunResult() const {
+  return last_migration_run_result_;
+}
+
 void AccountManagerMigrator::OnMigrationRunComplete(
     const AccountMigrationRunner::MigrationResult& result) {
   DCHECK_NE(AccountMigrationRunner::Status::kNotStarted,
@@ -574,6 +579,8 @@ void AccountManagerMigrator::OnMigrationRunComplete(
   DCHECK_NE(AccountMigrationRunner::Status::kRunning,
             migration_runner_.GetStatus());
 
+  last_migration_run_result_ = base::make_optional(result);
+
   VLOG(1) << "Account migrations completed with result: "
           << static_cast<int>(result.final_status);
   if (result.final_status == AccountMigrationRunner::Status::kFailure)

chrome/browser/chromeos/account_manager/account_manager_migrator.h

@@ -7,6 +7,7 @@
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "chrome/browser/chromeos/account_manager/account_migration_runner.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "components/keyed_service/core/keyed_service.h"
@@ -31,6 +32,11 @@ class AccountManagerMigrator : public KeyedService {
   // Gets the current status of migration.
   AccountMigrationRunner::Status GetStatus() const;
 
+  // Gets the result of the last migration run. If migrations have not been run
+  // before, the optional will be empty.
+  base::Optional<AccountMigrationRunner::MigrationResult>
+  GetLastMigrationRunResult() const;
+
  private:
   // Returns whether migrations should be run or skipped.
   bool ShouldRunMigrations() const;
@@ -55,6 +61,11 @@ class AccountManagerMigrator : public KeyedService {
   // migration flow to be a no-op, in which case this will be |false|.
   bool ran_migration_steps_ = false;
 
+  // Result of the last migration run. Empty if migrations have not been run
+  // before.
+  base::Optional<AccountMigrationRunner::MigrationResult>
+      last_migration_run_result_;
+
   base::WeakPtrFactory<AccountManagerMigrator> weak_factory_{this};
   DISALLOW_COPY_AND_ASSIGN(AccountManagerMigrator);
 };