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

sync/engine/process_commit_response_command.h

Index: sync/engine/process_commit_response_command.h
diff --git a/sync/engine/process_commit_response_command.h b/sync/engine/process_commit_response_command.h
index 80c5753c0f176501754b322c5e93ec7eb799ff52..ef5ab08222eec6865a6a872278d6c279bb570273 100644
--- a/sync/engine/process_commit_response_command.h
+++ b/sync/engine/process_commit_response_command.h
@@ -14,6 +14,12 @@
 #include "sync/engine/model_changing_syncer_command.h"
 #include "sync/engine/syncproto.h"
 
+namespace syncer {
+
+namespace sessions {
+class OrderedCommitSet;
+}
+
 namespace syncable {
 class Id;
 class WriteTransaction;
@@ -21,12 +27,6 @@ class MutableEntry;
 class Directory;
 }
 
-namespace syncer {
-
-namespace sessions {
-class OrderedCommitSet;
-}
-
 // A class that processes the server's response to our commmit attempt.  Note
 // that some of the preliminary processing is performed in
 // PostClientToServerMessage command.