sync: Inject sync/'s dependency on invalidations

sync/internal_api/public/base/invalidation.cc

Index: sync/internal_api/public/base/invalidation.cc
diff --git a/sync/internal_api/public/base/invalidation.cc b/sync/internal_api/public/base/invalidation.cc
index ff7a5a78fd4dc542856a768b08565552e1823150..059a0f9c3ec7958282e689109d0122e3b945950f 100644
--- a/sync/internal_api/public/base/invalidation.cc
+++ b/sync/internal_api/public/base/invalidation.cc
@@ -11,7 +11,6 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "sync/notifier/ack_handler.h"
-#include "sync/notifier/dropped_invalidation_tracker.h"
 #include "sync/notifier/invalidation_util.h"
 
 namespace syncer {
@@ -128,9 +127,7 @@ void Invalidation::Acknowledge() const {
   }
 }
 
-void Invalidation::Drop(DroppedInvalidationTracker* tracker) const {
-  DCHECK(tracker->object_id() == object_id());
-  tracker->RecordDropEvent(ack_handler_, ack_handle_);
+void Invalidation::Drop() {
   if (SupportsAcknowledgement()) {
     ack_handler_.Call(FROM_HERE,
                       &AckHandler::Drop,