[Sync] SyncEngine 1.5: Fix all backend references in PSS.

components/precache/content/precache_manager.cc

Index: components/precache/content/precache_manager.cc
diff --git a/components/precache/content/precache_manager.cc b/components/precache/content/precache_manager.cc
index f4333c12d64e9b02779ca6a8de304a99f2e8bcf5..3ac967b34b1acf9dce4da7a31ce8668db11b3f99 100644
--- a/components/precache/content/precache_manager.cc
+++ b/components/precache/content/precache_manager.cc
@@ -99,7 +99,7 @@ bool PrecacheManager::IsPrecachingAllowed() const {
 }
 
 PrecacheManager::AllowedType PrecacheManager::PrecachingAllowed() const {
-  if (!(sync_service_ && sync_service_->IsBackendInitialized()))
+  if (!(sync_service_ && sync_service_->IsEngineInitialized()))
     return AllowedType::PENDING;
 
   // SyncService delegates to SyncPrefs, which must be called on the UI thread.