Sanitize headers in Proxy Authentication Required responses

BUG=431504

Review URL: https://codereview.chromium.org/769043003

Cr-Commit-Position: refs/heads/master@{#310014}
CaptureGroupNameHttpProxySocketPool::CaptureGroupNameSocketPool(
    HostResolver* host_resolver,
    CertVerifier* /* cert_verifier */)
    : HttpProxyClientSocketPool(
          0, 0, NULL, host_resolver, NULL, NULL, NULL, NULL) {}

CaptureGroupNameHttpProxySocketPool::CaptureGroupNameSocketPool(
    HostResolver* host_resolver,
    CertVerifier* /* cert_verifier */)
    : HttpProxyClientSocketPool(
          0, 0, NULL, host_resolver, NULL, NULL, NULL, NULL) {}
