[Sync] Convert sync to a static library.

components/sync/base/unique_position.h

Index: components/sync/base/unique_position.h
diff --git a/components/sync/base/unique_position.h b/components/sync/base/unique_position.h
index bfb27f655f99d5486a9ebb4cd60511a439ec6c74..f205ce6311c4233fc681564350fd83ae572d219e 100644
--- a/components/sync/base/unique_position.h
+++ b/components/sync/base/unique_position.h
@@ -10,8 +10,6 @@
 
 #include <string>
 
-#include "components/sync/base/sync_export.h"
-
 namespace sync_pb {
 class UniquePosition;
 }
@@ -40,7 +38,7 @@ namespace syncer {
 //
 // This class currently has several bookmarks-related assumptions built in,
 // though it could be adapted to be more generally useful.
-class SYNC_EXPORT UniquePosition {
+class UniquePosition {
  public:
   static const size_t kSuffixLength;
   static const size_t kCompressBytesThreshold;