Refactor ModelTypePayloadMap and ObjectIdPayloadMap to StateMaps.

This lays the groundwork for allowing us to pass ack handles for object IDs to
SyncNotifierObservers.

BUG=124149
TEST=none, there should be no behavior change.


Review URL: https://chromiumcodereview.appspot.com/10837214

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153158 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/sync/notifier/invalidation_util.h b/sync/notifier/invalidation_util.h
index bc43523c..2f3198b 100644
--- a/sync/notifier/invalidation_util.h
+++ b/sync/notifier/invalidation_util.h
@@ -7,6 +7,7 @@
 #ifndef SYNC_NOTIFIER_INVALIDATION_UTIL_H_
 #define SYNC_NOTIFIER_INVALIDATION_UTIL_H_
 
+#include <iosfwd>
 #include <set>
 #include <string>
 
@@ -17,6 +18,9 @@
 class Invalidation;
 class ObjectId;
 
+// Gmock print helper
+void PrintTo(const invalidation::ObjectId& id, std::ostream* os);
+
 }  // namespace invalidation
 
 namespace syncer {