Revert 270308 "sync: Improve handling of bad UniquePositions"

trunk/src/sync/engine/syncer_util.cc

Index: trunk/src/sync/engine/syncer_util.cc
===================================================================
--- trunk/src/sync/engine/syncer_util.cc	(revision 270321)
+++ trunk/src/sync/engine/syncer_util.cc	(working copy)
@@ -12,7 +12,6 @@
 #include "base/base64.h"
 #include "base/location.h"
 #include "base/metrics/histogram.h"
-#include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "sync/engine/conflict_resolver.h"
 #include "sync/engine/syncer_proto_util.h"
@@ -279,9 +278,7 @@
 std::string GetUniqueBookmarkTagFromUpdate(const sync_pb::SyncEntity& update) {
   if (!update.has_originator_cache_guid() ||
       !update.has_originator_client_item_id()) {
-    LOG(ERROR) << "Update is missing requirements for bookmark position."
-               << " This is a server bug.";
-    return UniquePosition::RandomSuffix();
+    return std::string();
   }
 
   return syncable::GenerateSyncableBookmarkHash(
@@ -298,8 +295,7 @@
   } else if (update.has_position_in_parent()) {
     return UniquePosition::FromInt64(update.position_in_parent(), suffix);
   } else {
-    LOG(ERROR) << "No position information in update. This is a server bug.";
-    return UniquePosition::FromInt64(0, suffix);
+    return UniquePosition::CreateInvalid();
   }
 }
 
@@ -345,6 +341,10 @@
       GetUpdatePosition(update, local_entry->GetUniqueBookmarkTag());
   if (update_pos.IsValid()) {
     local_entry->PutServerUniquePosition(update_pos);
+  } else {
+    // TODO(sync): This and other cases of unexpected input should be handled
+    // better.
+    NOTREACHED();
   }
 }