[sync] Fix decryption failure caused by missing user_key

components/sync/base/nigori_unittest.cc

Index: components/sync/base/nigori_unittest.cc
diff --git a/components/sync/base/nigori_unittest.cc b/components/sync/base/nigori_unittest.cc
index 09bbcd75a4039044752a160cee2b5edcaea56335..4dd0e22585a47257e8fd4c3e48d645f9fb74038b 100644
--- a/components/sync/base/nigori_unittest.cc
+++ b/components/sync/base/nigori_unittest.cc
@@ -126,12 +126,13 @@ TEST(SyncNigoriTest, ExportImport) {
   Nigori nigori1;
   EXPECT_TRUE(nigori1.InitByDerivation("example.com", "username", "password"));
 
+  std::string user_key;
   std::string encryption_key;
   std::string mac_key;
-  EXPECT_TRUE(nigori1.ExportKeys(&encryption_key, &mac_key));
+  EXPECT_TRUE(nigori1.ExportKeys(&user_key, &encryption_key, &mac_key));
 
   Nigori nigori2;
-  EXPECT_TRUE(nigori2.InitByImport(encryption_key, mac_key));
+  EXPECT_TRUE(nigori2.InitByImport(user_key, encryption_key, mac_key));
 
   std::string original("test");
   std::string plaintext;
@@ -151,5 +152,30 @@ TEST(SyncNigoriTest, ExportImport) {
   EXPECT_EQ(permuted1, permuted2);
 }
 
+TEST(SyncNigoriTest, InitByDerivationSetsUserKey) {
+  Nigori nigori;
+  EXPECT_TRUE(nigori.InitByDerivation("example.com", "username", "password"));
+
+  std::string user_key = "";
+  std::string encryption_key;
+  std::string mac_key;
+  EXPECT_TRUE(nigori.ExportKeys(&user_key, &encryption_key, &mac_key));
+
+  EXPECT_NE(user_key, "");
+}
+
+TEST(SyncNigoriTest, InitByImportToleratesEmptyUserKey) {
+  Nigori nigori1;
+  EXPECT_TRUE(nigori1.InitByDerivation("example.com", "username", "password"));
+
+  std::string user_key;
+  std::string encryption_key;
+  std::string mac_key;
+  EXPECT_TRUE(nigori1.ExportKeys(&user_key, &encryption_key, &mac_key));
+
+  Nigori nigori2;
+  EXPECT_TRUE(nigori2.InitByImport("", encryption_key, mac_key));
+}
+
 }  // anonymous namespace
 }  // namespace syncer