[Sync] Add more info for invalid position check

sync/syncable/entry_kernel.h

Index: sync/syncable/entry_kernel.h
diff --git a/sync/syncable/entry_kernel.h b/sync/syncable/entry_kernel.h
index 6b627a46b8b9a6866182c339eed9d2a40907700d..bf023914e5d6cfff048dfc323aa91a02d66d83cf 100644
--- a/sync/syncable/entry_kernel.h
+++ b/sync/syncable/entry_kernel.h
@@ -124,8 +124,8 @@ enum StringField {
   // A tag string which identifies this node as a particular top-level
   // permanent object.  The tag can be thought of as a unique key that
   // identifies a singleton instance.
-  UNIQUE_SERVER_TAG,  // Tagged by the server
-  UNIQUE_CLIENT_TAG,  // Tagged by the client
+  UNIQUE_SERVER_TAG,    // Tagged by the server
+  UNIQUE_CLIENT_TAG,    // Tagged by the client
   UNIQUE_BOOKMARK_TAG,  // Client tags for bookmark items
   STRING_FIELDS_END,
 };
@@ -191,8 +191,6 @@ enum {
   BIT_TEMPS_COUNT = BIT_TEMPS_END - BIT_TEMPS_BEGIN
 };
 
-
-
 struct SYNC_EXPORT_PRIVATE EntryKernel {
  private:
   std::string string_fields[STRING_FIELDS_COUNT];
@@ -206,6 +204,8 @@ struct SYNC_EXPORT_PRIVATE EntryKernel {
   std::bitset<BIT_FIELDS_COUNT> bit_fields;
   std::bitset<BIT_TEMPS_COUNT> bit_temps;
 
+  friend std::ostream& operator<<(std::ostream& s, const EntryKernel& e);
+
  public:
   EntryKernel();
   ~EntryKernel();
@@ -393,6 +393,8 @@ base::DictionaryValue* EntryKernelMutationToValue(
 base::ListValue* EntryKernelMutationMapToValue(
     const EntryKernelMutationMap& mutations);
 
+std::ostream& operator<<(std::ostream& os, const EntryKernel& entry_kernel);
+
 }  // namespace syncable
 }  // namespace syncer