We could use libphonenumber to format the phone numbers correcty?

https://cs.chromium.org/chromium/src/third_party/libphonenumber/dist/cpp/src/phonenumbers/phonenumberutil.h?l=286

You can also use the built-in Android phone number formatter, which saves you from having to write JNI glue.

https://cs.chromium.org/chromium/src/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/EditorView.java?rcl=0&l=138

Beware that instantiating the formatter reads data from disk, so it should not be done in UI thread.

https://developer.android.com/reference/android/telephony/PhoneNumberUtils.html#formatNumber(java.lang.String, java.lang.String) is the function that you need to use.

After investigation, the built in Android formatted will not work because it does not give consistent results depending on OS version.

LibPhoneNumber could be used instead.

There is one big question to address in this case, how do we choose whether to format the number in it's national or international version. See examples here
https://cs.chromium.org/chromium/src/third_party/libphonenumber/dist/resources/phonenumber.proto?q=phonenumber.proto&sq=package:chromium&dr&l=106

Let's go with international for now.

Can you give some examples about what going with international would mean?

I still feel like the answer here is to strip everything except for a + if it exists

Here are some examples:

Google MTV, +1 650-253-0000
Google Paris, +33 (0)1 42 68 53 00
Google Beijing, +86-10-62503000

What's the benefit of formatting the phone number for a machine? We format for users. For machines, shouldn't we optimize for consistency?

I tend to agree with you.

My only concern is that it would be possible to send an "incomplete" phone number. As we check only very simply if the phone number is "valid". We use the Android PhoneNumberUtils' IsGlobalPhoneNumber which has a very loose sense of validity. For example, "55" is a valid phone number.

Here is what I propose:

1- Return Raw number (just numbers, maybe keep the "+")
2- Be more strict when deciding if a phone number is valid.

sgtm

I opened http://crbug.com/674978 and http://crbug.com/674976 to resolve these issues. Thanks.