We've had a few bugs in the past that have led to Chrome losing translations for locales.

One that affected Brazilian Portuguese (bug #691594)
And more recently, Filipino (bug #780331).

We really need to have tests that just launch Chrome in each supported locale, and checks that translations exist.

Since instrumentation tests have a different start-up flow from normal Chrome, it would be ideal if these tests did not use instrumentation (or, at least not our default instrumentation).

Here's an idea for testing .pak strings:
1. Use adb to change locale
2. Wipe app data
3. Launch Chrome with a URL about:version
4. Use devtools protocol to fetch the HTML and ensure it's translated (this validates strings from .pak files)
Note: telemetry already uses devtools protocol, so there's a client library for this already:
https://cs.chromium.org/chromium/src/third_party/android_tools/sdk/platform-tools/systrace/catapult/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py?rcl=4a9623af577555a8dab891c8789cc3dfe80addae&l=142


Here's an idea for testing .arsc strings:
1. Launch with URL: about:newtab
2. Dump view hierarchy:
adb -s 00b424b27f9028b4ml'ell 'uiautomator dump /data/local/tmp/dump.xml >/dev/null && cat /data/local/tmp/dump.xml'
3. Grep it for text="$EXPECTED_STRING"

Not sure if this would be best to write as a "python" test in test_runner.py, or a "perf" test. Many pieces of what I described is already done for perf tests, but I'm not very familiar with that code yet.