Revert 270308 "sync: Improve handling of bad UniquePositions"

trunk/src/sync/syncable/directory_backing_store.cc

Index: trunk/src/sync/syncable/directory_backing_store.cc
===================================================================
--- trunk/src/sync/syncable/directory_backing_store.cc	(revision 270322)
+++ trunk/src/sync/syncable/directory_backing_store.cc	(working copy)
@@ -123,16 +123,6 @@
     kernel->mutable_ref(static_cast<AttachmentMetadataField>(i)).ParseFromArray(
         statement->ColumnBlob(i), statement->ColumnByteLength(i));
   }
-
-  // Sanity check on positions.  We risk strange and rare crashes if our
-  // assumptions about unique position values are broken.
-  if (kernel->ShouldMaintainPosition() &&
-      !kernel->ref(UNIQUE_POSITION).IsValid()) {
-    DVLOG(1) << "Unpacked invalid position on an entity that should have a "
-             << "valid position.  Assuming the DB is corrupt.";
-    return scoped_ptr<EntryKernel>();
-  }
-
   return kernel.Pass();
 }