Factor getCertificateChain out of ConnectionPopupInfo

This patch refactors the GetCertificateChain logic out of
connection_info_popup_android.cc so we can share it between
ConnectionInfoPopup and PaymentRequestImpl.

BUG=587995

Review-Url: https://codereview.chromium.org/2567673002
Cr-Commit-Position: refs/heads/master@{#439237}
9 files changed