Substantially increase browser timeouts.

lib/src/runner/browser/server.dart

Index: lib/src/runner/browser/server.dart
diff --git a/lib/src/runner/browser/server.dart b/lib/src/runner/browser/server.dart
index 0740990ddce6742771733b4d207230c54c5f5906..1383bb3bc9e3423854a40b8b8d122639c22b8651 100644
--- a/lib/src/runner/browser/server.dart
+++ b/lib/src/runner/browser/server.dart
@@ -446,7 +446,7 @@ void main() {
       completer.completeError(error, stackTrace);
     });
 
-    return completer.future.timeout(new Duration(seconds: 7), onTimeout: () {
+    return completer.future.timeout(new Duration(seconds: 30), onTimeout: () {
       throw new ApplicationException(
           "Timed out waiting for ${platform.name} to connect.");
     });