Update corelib/ and lib/ to use the new try-catch syntax.

lib/html/src/Measurement.dart

Index: lib/html/src/Measurement.dart
diff --git a/lib/html/src/Measurement.dart b/lib/html/src/Measurement.dart
index 49bfffa67337f2e9b455d3b8829219f7721d7a8a..d68d4a0a57226a38ffae478e96a2ba765ebfb1f8 100644
--- a/lib/html/src/Measurement.dart
+++ b/lib/html/src/Measurement.dart
@@ -90,7 +90,7 @@ void _completeMeasurementFutures() {
     for (_MeasurementRequest request in _pendingRequests) {
       try {
         request.value = request.computeValue();
-      } catch(var e) {
+      } catch (e) {
         request.value = e;
         request.exception = true;
       }