Updated CustomTabsHelper#getPackageNameToUse

[codeversed]

Previously, if a default browser was set that did not support CustomTabs, this would return sPackageNameToUse as null. queryIntentActivites needs to have the PackageManager.MATCH_ALL flag (MATCH_DEFAULT_ONLY for < M).

[googlebot]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please visit https://cla.developers.google.com/ to sign.

Once you've signed, please reply here (e.g. I signed it!) and we'll verify. Thanks.

---

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If you signed the CLA as a corporation, please let us know the company's name.

[codeversed]

I signed it!

[talklittle]

Missing import:

import android.os.Build;

[andistuder]

IMO this has been addressed in 7a2c137 - maybe close this PR?