[Sync] Convert sync to a static library.

components/sync/base/cancelation_signal.h

Index: components/sync/base/cancelation_signal.h
diff --git a/components/sync/base/cancelation_signal.h b/components/sync/base/cancelation_signal.h
index 9189b4705f4d26809048aef97a11f1d84797611d..6740743f8e129d6facc3e3960bcf245439c0e6f1 100644
--- a/components/sync/base/cancelation_signal.h
+++ b/components/sync/base/cancelation_signal.h
@@ -6,7 +6,6 @@
 #define COMPONENTS_SYNC_BASE_CANCELATION_SIGNAL_H_
 
 #include "base/synchronization/lock.h"
-#include "components/sync/base/sync_export.h"
 
 namespace syncer {
 
@@ -31,7 +30,7 @@ class CancelationObserver;
 //
 // This class supports only one handler, though it could easily support multiple
 // observers if we found a use case for such a feature.
-class SYNC_EXPORT CancelationSignal {
+class CancelationSignal {
  public:
   CancelationSignal();
   ~CancelationSignal();