sync: migrate invalidation state from syncable::Directory to InvalidationStorage

sync/notifier/invalidation_notifier.cc

Index: sync/notifier/invalidation_notifier.cc
diff --git a/sync/notifier/invalidation_notifier.cc b/sync/notifier/invalidation_notifier.cc
index c86a50251244fd4b9239049830281efb30642895..e188adb94865224d695454303121762e93d5d009 100644
--- a/sync/notifier/invalidation_notifier.cc
+++ b/sync/notifier/invalidation_notifier.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "base/message_loop_proxy.h"
+#include "base/metrics/histogram.h"
 #include "jingle/notifier/listener/push_client.h"
 #include "net/url_request/url_request_context.h"
 #include "sync/notifier/sync_notifier_observer.h"
@@ -18,6 +19,7 @@ namespace sync_notifier {
 InvalidationNotifier::InvalidationNotifier(
     scoped_ptr<notifier::PushClient> push_client,
     const InvalidationVersionMap& initial_max_invalidation_versions,
+    const std::string& initial_invalidation_state,
     const browser_sync::WeakHandle<InvalidationStateTracker>&
         invalidation_state_tracker,
     const std::string& client_info)
@@ -25,6 +27,7 @@ InvalidationNotifier::InvalidationNotifier(
       initial_max_invalidation_versions_(initial_max_invalidation_versions),
       invalidation_state_tracker_(invalidation_state_tracker),
       client_info_(client_info),
+      invalidation_state_(initial_invalidation_state),
       invalidation_client_(push_client.Pass()) {
 }
 
@@ -49,10 +52,24 @@ void InvalidationNotifier::SetUniqueId(const std::string& unique_id) {
   CHECK(!invalidation_client_id_.empty());
 }
 
-void InvalidationNotifier::SetState(const std::string& state) {
+void InvalidationNotifier::SetStateDeprecated(const std::string& state) {
   DCHECK(non_thread_safe_.CalledOnValidThread());
-  invalidation_state_ = state;
-  DVLOG(1) << "Setting new state";
+  DCHECK_LT(state_, STARTED);
+  if (invalidation_state_.empty()) {
+    // Migrate state from sync to invalidation state tracker (bug
+    // 124140).  We've just been handed state from the syncable::Directory, and
+    // the initial invalidation state was empty, implying we've never written
+    // to the new store. Do this here to ensure we always migrate (even if
+    // we fail to establish an initial connection or receive an initial
+    // invalidation) so that we can make the old code obsolete as soon as
+    // possible.
+    invalidation_state_ = state;
+    invalidation_state_tracker_.Call(
+        FROM_HERE, &InvalidationStateTracker::SetInvalidationState, state);
+    UMA_HISTOGRAM_BOOLEAN("InvalidationNotifier.UsefulSetState", true);
+  } else {
+    UMA_HISTOGRAM_BOOLEAN("InvalidationNotifier.UsefulSetState", false);
+  }
 }
 
 void InvalidationNotifier::UpdateCredentials(
@@ -62,7 +79,7 @@ void InvalidationNotifier::UpdateCredentials(
         invalidation_client_id_, client_info_, invalidation_state_,
         initial_max_invalidation_versions_,
         invalidation_state_tracker_,
-        this, this);
+        this);
     invalidation_state_.clear();
     state_ = STARTED;
   }
@@ -95,10 +112,4 @@ void InvalidationNotifier::OnSessionStatusChanged(bool has_session) {
                     OnNotificationStateChange(has_session));
 }
 
-void InvalidationNotifier::WriteState(const std::string& state) {
-  DCHECK(non_thread_safe_.CalledOnValidThread());
-  DVLOG(1) << "WriteState";
-  FOR_EACH_OBSERVER(SyncNotifierObserver, observers_, StoreState(state));
-}
-
 }  // namespace sync_notifier