Rename blahHandler to onBlah throughout dart:io.

tools/testing/dart/status_file_parser.dart

Index: tools/testing/dart/status_file_parser.dart
diff --git a/tools/testing/dart/status_file_parser.dart b/tools/testing/dart/status_file_parser.dart
index 58e24831d55f2c2d489390d7f14cbcd02d3cc9b1..c23e00d06a0eff2c9c634240391fd6f7c20328c5 100644
--- a/tools/testing/dart/status_file_parser.dart
+++ b/tools/testing/dart/status_file_parser.dart
@@ -66,7 +66,7 @@ void ReadConfigurationInto(path, sections, onDone) {
   sections.add(current);
   String prefix = "";
 
-  lines.lineHandler = () {
+  lines.onLine = () {
     String line;
     while ((line = lines.readLine()) != null) {
       Match match = StripComment.firstMatch(line);
@@ -106,7 +106,7 @@ void ReadConfigurationInto(path, sections, onDone) {
     }
   };
 
-  lines.closeHandler = () {
+  lines.onClose = () {
     onDone();
   };
 }