[Sync] Refactor passphrase state handling

chrome/browser/sync/glue/sync_backend_host.cc

Index: chrome/browser/sync/glue/sync_backend_host.cc
diff --git a/chrome/browser/sync/glue/sync_backend_host.cc b/chrome/browser/sync/glue/sync_backend_host.cc
index 679dad943280fc2d38073485a73cbfe23882a4f7..adfa8f6cd21a1781dda33dda68a45840f06912bd 100644
--- a/chrome/browser/sync/glue/sync_backend_host.cc
+++ b/chrome/browser/sync/glue/sync_backend_host.cc
@@ -48,6 +48,7 @@
 #include "sync/internal_api/public/read_transaction.h"
 #include "sync/internal_api/public/sync_manager_factory.h"
 #include "sync/internal_api/public/util/experiments.h"
+#include "sync/internal_api/public/util/sync_string_conversions.h"
 #include "sync/notifier/sync_notifier.h"
 #include "sync/protocol/encryption.pb.h"
 #include "sync/protocol/sync.pb.h"
@@ -115,6 +116,7 @@ class SyncBackendHost::Core
   virtual void OnEncryptionComplete() OVERRIDE;
   virtual void OnCryptographerStateChanged(
       syncer::Cryptographer* cryptographer) OVERRIDE;
+  virtual void OnPassphraseStateChanged(syncer::PassphraseState state) OVERRIDE;
 
   // syncer::SyncNotifierObserver implementation.
   virtual void OnNotificationsEnabled() OVERRIDE;
@@ -325,7 +327,8 @@ SyncBackendHost::SyncBackendHost(
                                profile_->GetRequestContext()),
           content::GetUserAgent(GURL()),
           invalidator_storage),
-      frontend_(NULL) {
+      frontend_(NULL),
+      cached_passphrase_state_(syncer::IMPLICIT_PASSPHRASE) {
 }
 
 SyncBackendHost::SyncBackendHost(Profile* profile)
@@ -340,7 +343,8 @@ SyncBackendHost::SyncBackendHost(Profile* profile)
                                profile_->GetRequestContext()),
           content::GetUserAgent(GURL()),
           base::WeakPtr<syncer::InvalidationStateTracker>()),
-      frontend_(NULL) {
+      frontend_(NULL),
+      cached_passphrase_state_(syncer::IMPLICIT_PASSPHRASE) {
 }
 
 SyncBackendHost::~SyncBackendHost() {
@@ -762,11 +766,11 @@ bool SyncBackendHost::IsUsingExplicitPassphrase() {
   // otherwise we have no idea what kind of passphrase we are using. This will
   // NOTREACH in sync_manager and return false if we fail to load the nigori
   // node.
-  // TODO(zea): cache this value here, then make the encryption handler
-  // NonThreadSafe and only accessible from the sync thread.
-  return IsNigoriEnabled() &&
-      core_->sync_manager()->GetEncryptionHandler()->
-          IsUsingExplicitPassphrase();
+  // TODO(zea): expose whether the custom passphrase is a frozen implicit
+  // passphrase or not to provide better messaging.
+  return IsNigoriEnabled() && (
+      cached_passphrase_state_ == syncer::CUSTOM_PASSPHRASE ||
+      cached_passphrase_state_ == syncer::FROZEN_IMPLICIT_PASSPHRASE);
 }
 
 bool SyncBackendHost::IsCryptographerReady(
@@ -1025,6 +1029,14 @@ void SyncBackendHost::Core::OnCryptographerStateChanged(
   // Do nothing.
 }
 
+void SyncBackendHost::Core::OnPassphraseStateChanged(
+    syncer::PassphraseState state) {
+  host_.Call(
+      FROM_HERE,
+      &SyncBackendHost::HandlePassphraseStateChangedOnFrontendLoop,
+      state);
+}
+
 void SyncBackendHost::Core::OnActionableError(
     const syncer::SyncProtocolError& sync_error) {
   if (!sync_loop_)
@@ -1166,6 +1178,9 @@ void SyncBackendHost::Core::DoAssociateNigori() {
   sync_manager_->GetEncryptionHandler()->AddObserver(this);
   sync_manager_->GetEncryptionHandler()->Init();
   host_.Call(FROM_HERE,
+             &SyncBackendHost::HandlePassphraseStateChangedOnFrontendLoop,
+             sync_manager_->GetEncryptionHandler()->GetPassphraseState());
+  host_.Call(FROM_HERE,
              &SyncBackendHost::HandleInitializationCompletedOnFrontendLoop,
              true);
 }
@@ -1519,6 +1534,14 @@ void SyncBackendHost::NotifyEncryptionComplete() {
   frontend_->OnEncryptionComplete();
 }
 
+void SyncBackendHost::HandlePassphraseStateChangedOnFrontendLoop(
+    syncer::PassphraseState state) {
+  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DVLOG(1) << "Passphrase state changed to "
+           << syncer::PassphraseStateToString(state);
+  cached_passphrase_state_ = state;
+}
+
 void SyncBackendHost::HandleStopSyncingPermanentlyOnFrontendLoop() {
   if (!frontend_)
     return;