This function is an infallible alternative to nsIURI::GetSpec(). It's useful
when it's appropriate to handle a GetSpec() failure with a failure string, e.g.
for log/warning/error messages. It allows code like this:
nsAutoCString spec;
uri->GetSpec(spec);
printf("uri: %s", spec.get());
to be changed to this:
printf("uri: %s", uri->GetSpecOrDefault().get());
This introduces a slight behavioural change. Previously, if GetSpec() failed,
an empty string would be used here. Now, "[nsIURI::GetSpec failed]" will be
produced instead. In most cases this failure string will make for a clearer
log/warning/error message than the empty string.
* * *
Bug 1297961 (part 1b) - More GetSpecOrDefault() additions. r=hurley.
I will fold this into part 1 before landing.