[Sync] Allow sync start without sign-in if the local sync backend is on.

components/sync/engine_impl/sync_manager_impl_unittest.cc

Index: components/sync/engine_impl/sync_manager_impl_unittest.cc
diff --git a/components/sync/engine_impl/sync_manager_impl_unittest.cc b/components/sync/engine_impl/sync_manager_impl_unittest.cc
index 8bc45bbdf488decd3ba5b5aa249e6f8a296b20b4..dad760c04b84c6581738fa459947dbca36d209ac 100644
--- a/components/sync/engine_impl/sync_manager_impl_unittest.cc
+++ b/components/sync/engine_impl/sync_manager_impl_unittest.cc
@@ -996,8 +996,7 @@ class SyncManagerTest : public testing::Test,
 
   virtual ~SyncManagerTest() {}
 
-  // Test implementation.
-  void SetUp() {
+  virtual void DoSetUp(bool enable_local_sync_backend) {
     ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
 
     extensions_activity_ = new ExtensionsActivity();
@@ -1035,8 +1034,11 @@ class SyncManagerTest : public testing::Test,
     args.workers = workers;
     args.extensions_activity = extensions_activity_.get(),
     args.change_delegate = this;
-    args.credentials = credentials;
+    if (!enable_local_sync_backend)
+      args.credentials = credentials;
     args.invalidator_client_id = "fake_invalidator_client_id";
+    args.enable_local_sync_backend = enable_local_sync_backend;
+    args.local_sync_backend_folder = temp_dir_.GetPath();
     args.engine_components_factory.reset(GetFactory());
     args.encryptor = &encryptor_;
     args.unrecoverable_error_handler =
@@ -1060,6 +1062,9 @@ class SyncManagerTest : public testing::Test,
     PumpLoop();
   }
 
+  // Test implementation.
+  void SetUp() { DoSetUp(false); }
+
   void TearDown() {
     sync_manager_.RemoveObserver(&manager_observer_);
     sync_manager_.ShutdownOnSyncThread(STOP_SYNC);
@@ -2692,6 +2697,40 @@ TEST_F(SyncManagerTest, IncrementTransactionVersion) {
   }
 }
 
+#if defined(OS_WIN)

[Nicolas Zea, 2016/12/15 00:37:28]

May as well remove the OS requirement here right? The test should pass no matter
the platform.

[pastarmovj, 2016/12/16 17:04:48]

Actually I added it after I tried compiling on the linux bots.

[Nicolas Zea, 2016/12/16 18:50:35]

That implies to me a layering violation. Everything in the engine should ideally
be abstracted from platform specific conditions. What was the error?

[pastarmovj, 2016/12/19 11:12:00]

it is because of this ifdef here:
https://cs.chromium.org/chromium/src/components/sync/engine_impl/sync_manager...
the reason for it is that all the local backend code is conditionally compiled
only in the Windows version for now to avoid bloating the executable on other
platforms as discussed here https://codereview.chromium.org/2360703002/#msg14 . 

I think it will be hard to get this done in any other way but to always compile
the code in on all platforms that run this test.

+class SyncManagerWithLocalBackendTest : public SyncManagerTest {
+ protected:
+  void SetUp() override { DoSetUp(true); }
+};
+
+// This test checks that we can successfully initialize without credentials in
+// the local backend case.
+TEST_F(SyncManagerWithLocalBackendTest, StartSyncInLocalMode) {
+  EXPECT_TRUE(SetUpEncryption(WRITE_TO_NIGORI, DEFAULT_ENCRYPTION));
+  EXPECT_CALL(encryption_observer_, OnEncryptionComplete());
+  EXPECT_CALL(encryption_observer_, OnCryptographerStateChanged(_));
+  EXPECT_CALL(encryption_observer_, OnEncryptedTypesChanged(_, false));
+
+  sync_manager_.GetEncryptionHandler()->Init();
+  PumpLoop();
+
+  const ModelTypeSet encrypted_types = GetEncryptedTypes();
+  EXPECT_TRUE(encrypted_types.Has(PASSWORDS));
+  EXPECT_FALSE(IsEncryptEverythingEnabledForTest());
+
+  {
+    ReadTransaction trans(FROM_HERE, sync_manager_.GetUserShare());
+    ReadNode node(&trans);
+    EXPECT_EQ(BaseNode::INIT_OK, node.InitByIdLookup(GetIdForDataType(NIGORI)));
+    sync_pb::NigoriSpecifics nigori = node.GetNigoriSpecifics();
+    EXPECT_TRUE(nigori.has_encryption_keybag());
+    Cryptographer* cryptographer = trans.GetCryptographer();
+    EXPECT_TRUE(cryptographer->is_ready());
+    EXPECT_TRUE(cryptographer->CanDecrypt(nigori.encryption_keybag()));
+  }
+}
+#endif  // defined(OS_WIN)
+
 class MockSyncScheduler : public FakeSyncScheduler {
  public:
   MockSyncScheduler() : FakeSyncScheduler() {}
@@ -2717,7 +2756,8 @@ class ComponentsFactory : public TestEngineComponentsFactory {
   std::unique_ptr<SyncScheduler> BuildScheduler(
       const std::string& name,
       SyncCycleContext* context,
-      CancelationSignal* stop_handle) override {
+      CancelationSignal* stop_handle,
+      bool local_sync_backend_enabled) override {
     *cycle_context_ = context;
     return std::move(scheduler_to_use_);
   }