Rename blahHandler to onBlah throughout dart:io.

runtime/bin/list_stream_impl.dart

Index: runtime/bin/list_stream_impl.dart
diff --git a/runtime/bin/list_stream_impl.dart b/runtime/bin/list_stream_impl.dart
index 7048922cbe54fc89c4e66a86d4d61807a67cb590..d148bfffee00312ca8352581a782fcb545837fa2 100644
--- a/runtime/bin/list_stream_impl.dart
+++ b/runtime/bin/list_stream_impl.dart
@@ -73,16 +73,16 @@ class _ListOutputStream implements ListOutputStream {
     close();
   }
 
-  void set noPendingWriteHandler(void callback()) {
+  void set onNoPendingWrites(void callback()) {
     _clientNoPendingWriteHandler = callback;
     _checkScheduleCallbacks();
   }
 
-  void set closeHandler(void callback()) {
+  void set onClosed(void callback()) {
     _clientCloseHandler = callback;
   }
 
-  void set errorHandler(void callback()) {
+  void set onError(void callback()) {
     // No errors emitted.
   }