No functional change yet because all probers still return 1 candidate.
Yet now we add a GetCandidates() method to return a number of
candidates.
GetCharSetName(), GetLanguage() and GetConfidence() now take a parameter
which is the candidate index (which must be below the return value of
GetCandidates()). We can now consider that nsCharSetProber computes a
couple (charset, language) and that the confidence is for this specific
couple, not just the confidence for charset detection.
Now the UTF-8 prober would not only detect valid UTF-8, but would also
detect the most probable language. Using the data generated 2 commits
away, this works very well.
This is still basic and will require even more improvements. In
particular, now the nsUTF8Prober should return an array of ("UTF-8",
language) couple candidate. And nsMBCSGroupProber should itself forward
these candidates as well as other candidates from other multi-byte
detectors. This way, the public-facing API would get more probable
candidates, in case the algorithm is slightly wrong.
Also the UTF-8 confidence is currently stupidly high as soon as we
consider it to be right. We should likely weigh it with language
detection (in particular, if no language is detected, this should
severely weigh down UTF-8 detection; not to 0, but high enough to be a
fallback in case no other encoding+lang is valid and low enough to give
chances to other good candidate couples.
