[Sync] Move sync/{internal_api,syncable} into syncer namespace

sync/internal_api/public/base_node.h

Index: sync/internal_api/public/base_node.h
diff --git a/sync/internal_api/public/base_node.h b/sync/internal_api/public/base_node.h
index 4b1924f5f979e349c9a2a41fb12bd8d8ed0276a6..666c2315a914b8cd997a655dac057e308e257d45 100644
--- a/sync/internal_api/public/base_node.h
+++ b/sync/internal_api/public/base_node.h
@@ -22,11 +22,6 @@ namespace base {
 class DictionaryValue;
 }
 
-namespace syncable {
-class BaseTransaction;
-class Entry;
-}
-
 namespace sync_pb {
 class AppSpecifics;
 class AutofillSpecifics;
@@ -46,6 +41,11 @@ namespace syncer {
 
 class BaseTransaction;
 
+namespace syncable {
+class BaseTransaction;
+class Entry;
+}
+
 // A valid BaseNode will never have an ID of zero.
 static const int64 kInvalidId = 0;