Unify most of our utf8 implementations. This takes the implementation

frog/file_system_vm.dart

Index: frog/file_system_vm.dart
===================================================================
--- frog/file_system_vm.dart	(revision 4630)
+++ frog/file_system_vm.dart	(working copy)
@@ -5,7 +5,7 @@
 #library('file_system_vm');
 #import('dart:io');
 #import('file_system.dart');
-#import('dart:utf8');
+#import('dart:utf');
 
 /** File system implementation using the vm api's. */
 class VMFileSystem implements FileSystem {
@@ -22,7 +22,7 @@
     var buffer = new List<int>(length);
     var bytes = file.readListSync(buffer, 0, length);
     file.closeSync();
-    return new String.fromCharCodes(Utf8Decoder.decodeUtf8(buffer));
+    return decodeUtf8(buffer);

[ahe, 2012/02/29 13:23:02]

Please keep the explicit call to new String.fromCharCodes. I think it is
important that it is obvious that this method copies the input three times.

[dgrove, 2012/03/02 12:34:30]

decodeUtf8 returns a String, while string.fromCharCodes expects a List. I don't
understand why it makes sense to keep this call (not to mention the fact that it
doesn't work when I leave this call in).
On 2012/02/29 13:23:02, ahe wrote:

[ahe, 2012/03/05 12:55:53]

Doesn't this work:

return new String.fromCharCodes(new Utf8Decoder(list).decodeRest());

[dgrove, 2012/03/05 13:35:13]

Done.

   }
 
   bool fileExists(String filename) {