[Sync] Adding integration tests for USS encryption and fixing a worker bug.

components/sync/engine_impl/model_type_worker.h

Index: components/sync/engine_impl/model_type_worker.h
diff --git a/components/sync/engine_impl/model_type_worker.h b/components/sync/engine_impl/model_type_worker.h
index 4d480415e6d4a96e9119fb49e70a73e7abd0ba2c..f033414fdec1ea69a06512deaccea3796ffd0bc1 100644
--- a/components/sync/engine_impl/model_type_worker.h
+++ b/components/sync/engine_impl/model_type_worker.h
@@ -88,6 +88,10 @@ class ModelTypeWorker : public UpdateHandler,
   std::unique_ptr<CommitContribution> GetContribution(
       size_t max_entries) override;
 
+  // An alternative way way to drive sending data to the processor, that should

[maxbogue, 2016/10/19 22:15:43]

s/way way/way

[skym, 2016/10/20 15:47:15]

Done.

+  // be called when a new encryption mechanism is ready.
+  void EncryptionAcceptedApplyUpdates();
+
   // Callback for when our contribution gets a response.
   void OnCommitResponse(CommitResponseDataList* response_list);
 
@@ -109,6 +113,10 @@ class ModelTypeWorker : public UpdateHandler,
   // settings in a good state.
   bool CanCommitItems() const;
 
+  // Returns true if this type should stop communicating because of outstanding
+  // encryption issues. Must wait for keys to be updated.

[maxbogue, 2016/10/19 22:15:43]

issues and must wait

[skym, 2016/10/20 15:47:15]

Done.

+  bool BlockForEncryption() const;
+
   // Takes |commit_entity| populated from fields of WorkerEntityTracker and
   // adjusts some fields before committing to server. Adjustments include
   // generating client-assigned ID, encrypting data, etc.
@@ -120,6 +128,17 @@ class ModelTypeWorker : public UpdateHandler,
   // keys to the processor to trigger re-encryption if necessary.
   void OnCryptographerUpdated();
 
+  // Returns whether the encryption key name is different between

[maxbogue, 2016/10/19 22:15:43]

The way this is phrased does not make it immediately clear that this function
has a side effect. I would switch the order so it's more like "updates blah if
necessary and returns whether an update occurred"

[skym, 2016/10/20 15:47:15]

Done.

+  // |cryptographer_| and |model_type_state_|. When a difference is found, the
+  // value in |cryptographer_| is copied to |model_type_state_|.
+  bool UpdateEncryptionKeyName();
+
+  // Iterates through all elements in |entities_| and tries to decrypt anything
+  // that has encrytped data. Also updates |has_encryted_updates_| to reflect

[maxbogue, 2016/10/19 22:15:43]

encrypted

[skym, 2016/10/20 15:47:15]

Done.

+  // whether anything in |entities_| was not decryptable by |cryptographer_|.
+  // Should only be called during a GetUpdates cycle.
+  void DecryptedStoredEntities();
+
   // Attempts to decrypt the given specifics and return them in the |out|
   // parameter. Assumes cryptographer_->CanDecrypt(specifics) returned true.
   //
@@ -173,6 +192,9 @@ class ModelTypeWorker : public UpdateHandler,
   // they can all be sent to the processor at once.
   UpdateResponseDataList pending_updates_;
 
+  // If there are outstanding encrypted updates in |entities_|.

[maxbogue, 2016/10/19 22:15:43]

s/If/Whether

[skym, 2016/10/20 15:47:15]

Done.

+  bool has_encryted_updates_;

[skym, 2016/10/19 19:22:16]

incorrectly spelled.

[skym, 2016/10/20 15:47:15]

Done.

+
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<ModelTypeWorker> weak_ptr_factory_;
 };