[Sync] Add location parameter to SyncChange in Sync API.

sync/api/sync_change.h

Index: sync/api/sync_change.h
diff --git a/sync/api/sync_change.h b/sync/api/sync_change.h
index 63a03d9606c3496d107ae22c907a4ae7d1b2b5c0..3cfb1d5d742e174320b017ede6ee3afc63d3e9cf 100644
--- a/sync/api/sync_change.h
+++ b/sync/api/sync_change.h
@@ -10,6 +10,7 @@
 #include <string>
 #include <vector>
 
+#include "base/location.h"
 #include "sync/api/sync_data.h"
 
 namespace syncer {
@@ -31,7 +32,10 @@ class SyncChange {
   // Default constructor creates an invalid change.
   SyncChange();
   // Create a new change with the specified sync data.
-  SyncChange(SyncChangeType change_type, const SyncData& sync_data);
+  SyncChange(
+      const tracked_objects::Location& from_here,
+      SyncChangeType change_type,
+      const SyncData& sync_data);
   ~SyncChange();
 
   // Copy constructor and assignment operator welcome.
@@ -56,6 +60,8 @@ class SyncChange {
   std::string ToString() const;
 
  private:
+  tracked_objects::Location location_;
+
   SyncChangeType change_type_;
 
   // An immutable container for the data of this SyncChange. Whenever