If Chrome is an app bundle with language splits it can happen that it starts in a language other than the system language (see b/119244673 for more context). We should track via UMA how often this happens. More specifically, report an enum histogram with the following values:

1. Chrome language equals system language.
2. Chrome language is fallback language (en) while system language is not en.
3. Chrome language is not system language but also not fallback language (en).

heamy@, digit@, benmason@ can you verify that this is what we want? I'm not sure about 3. above. It could be that this never happens and we can merge it with 2.
 

If Chrome is an app bundle with language splits it can happen that it starts in a language other than the system language (see b/119244673 for more context). We should track via UMA how often this happens. More specifically, implement metrics 3 and 3 in [1]:

# Metric 2

The number of times Chrome starts/resumes in a language other than the system language but we support the system language. This requires language splits to be turned on. It will tell us whether regular language splits are sufficient and is therefore also a predictor whether we can launch in Stable. We currently have language splits turned on in Canary and Dev. To get more metrics we could also turn them on in Beta.

Histogram name: Android.Language.WrongLanguageAfterResume
Histogram type: Boolean

# Metric 3

The duration from Chrome starting in a language other than the system language and we support the system language until it starts in that system language. This can reveal whether certain groups have an oddly high latency and/or a potential bug. This also requires language splits to be turned on.

Histogram name: Android.Language.DurationUntilCorrectLanguageApplied
Histogram type: Time

[1] https://docs.google.com/document/d/1_bOFM-xOYkzW_XccIijh-zNutzsNRcGGYylVl9ivBhI