We should use UserID object to identify users instead of username.

chrome/browser/browsing_data/browsing_data_remover.cc

Index: chrome/browser/browsing_data/browsing_data_remover.cc
diff --git a/chrome/browser/browsing_data/browsing_data_remover.cc b/chrome/browser/browsing_data/browsing_data_remover.cc
index ed3f118627089cbf80251f2415b93add01d68fd6..b09438849165dbd586967f27a07429d337064c80 100644
--- a/chrome/browser/browsing_data/browsing_data_remover.cc
+++ b/chrome/browser/browsing_data/browsing_data_remover.cc
@@ -703,7 +703,7 @@ void BrowsingDataRemover::RemoveImpl(int remove_mask,
       chromeos::DBusThreadManager::Get()->GetCryptohomeClient()->
           TpmAttestationDeleteKeys(
               chromeos::attestation::KEY_USER,
-              user->email(),
+              user->GetUserID(),
               chromeos::attestation::kContentProtectionKeyPrefix,
               base::Bind(&BrowsingDataRemover::OnClearPlatformKeys,
                          base::Unretained(this)));