Converting XHR from onLoad to onReadyStateChange

tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate

Index: tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate b/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
index 078d873b230c53637867d92323a520d0ae3bedda..70667a17474db8d0eac4499fa70a026ed26ad48d 100644
--- a/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
+++ b/tools/dom/templates/html/impl/impl_XMLHttpRequest.darttemplate
@@ -95,8 +95,9 @@ $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
     }
 
     xhr.onLoad.listen((e) {
-      if (xhr.status >= 200 && xhr.status < 300 ||
-          xhr.status == 304 ) {
+      // Note: file:// URIs have status of 0.
+      if ((xhr.status >= 200 && xhr.status < 300) ||
+          xhr.status == 0 || xhr.status == 304) {

[Emily Fortuna, 2013/02/07 20:55:50]

note -- please add in the comments of this method that if you are doing an xhr
request for a file:// URI, completeError WILL NEVER FIRE -- because the status
will be 0, regardless of whether the file is found or not.

         completer.complete(xhr);
       } else {
         completer.completeError(e);

[Siggi Cherem (dart-lang), 2013/02/07 21:03:30]

not for this CL, but we should also consider whether the error should be 'e'
should be the event or a special error object (maybe that points to both xhr and
the event?).

When I got the error object I wasn't sure how to use it. Turns out I really
wanted to use xhr to inspect what was happening.