Fix build error with gcc 4.9.3

chrome/browser/password_manager/native_backend_kwallet_x.cc

Index: chrome/browser/password_manager/native_backend_kwallet_x.cc
diff --git a/chrome/browser/password_manager/native_backend_kwallet_x.cc b/chrome/browser/password_manager/native_backend_kwallet_x.cc
index a9519aa24c013a8a05a1a4bdd0bd41f14a2c8e97..08813a245c2d3b7287a582acc31c6ecf85931502 100644
--- a/chrome/browser/password_manager/native_backend_kwallet_x.cc
+++ b/chrome/browser/password_manager/native_backend_kwallet_x.cc
@@ -388,6 +388,9 @@ NativeBackendKWallet::InitResult NativeBackendKWallet::InitWallet() {
     case KWalletDBus::Error::SUCCESS:
       return INIT_SUCCESS;
   }
+
+  NOTREACHED();
+  return PERMANENT_FAIL;
 }
 
 password_manager::PasswordStoreChangeList NativeBackendKWallet::AddLogin(