[WIP] Use public _registerService RPC

packages/flutter_tools/lib/src/vmservice.dart

diff --git a/packages/flutter_tools/lib/src/vmservice.dart b/packages/flutter_tools/lib/src/vmservice.dart
index 31dd369..b05aa2d 100644
--- a/packages/flutter_tools/lib/src/vmservice.dart
+++ b/packages/flutter_tools/lib/src/vmservice.dart
@@ -140,7 +140,7 @@
 
       // If the Flutter Engine doesn't support service registration this will
       // have no effect
-      _peer.sendNotification('_registerService', <String, String>{
+      _peer.sendNotification('registerService', <String, String>{
         'service': 'reloadSources',
         'alias': 'Flutter Tools',
       });
@@ -166,7 +166,7 @@
 
       // If the Flutter Engine doesn't support service registration this will
       // have no effect
-      _peer.sendNotification('_registerService', <String, String>{
+      _peer.sendNotification('registerService', <String, String>{
         'service': 'hotRestart',
         'alias': 'Flutter Tools',
       });
@@ -204,7 +204,7 @@
         }
       });
 
-      _peer.sendNotification('_registerService', <String, String>{
+      _peer.sendNotification('registerService', <String, String>{
         'service': 'compileExpression',
         'alias': 'Flutter Tools',
       });