Create array of extension views without side effects

BUG=608104

Review-Url: https://codereview.chromium.org/1935953002
Cr-Commit-Position: refs/heads/master@{#390961}
(cherry picked from commit aa7a889002dd7a1288cc5e962086e517131fb01e)

Review URL: https://codereview.chromium.org/1948773002 .

Cr-Commit-Position: refs/branch-heads/2704@{#362}
Cr-Branched-From: 6e53600def8f60d8c632fadc70d7c1939ccea347-refs/heads/master@{#386251}
1 file changed