The Fennec CrashReporter class is also renamed to
CrashReporterActivity. When running in Fennec, the Activity will be used
which retains what we do today, prompting for comments, email, etc. When
used in standalone GeckoView, we report the crash without user
interaction if the appropriate GeckoRuntimeSetting was set. The app will
want to ask for user permission at least once in order to set this.

We do not collect the URL, email, or logcat with GeckoView crashes.
Logcat and URL would be nice to have, but it's not clear what the API
for those would look like, and they can be addressed in followup
patches.

MozReview-Commit-ID: C5ROsUKreRe