GitLab

BUG=652872,652389
TEST=run_chrome_public_test_apk --verbose --gtest_filter=org.chromium.chrome.browser.media.remote.* on both low end and not a low end device.

Since https://codereview.chromium.org/2344353003 on low-end and JB devices videos
are not preloaded so we have to trigger that in a button onclick handler.

Review-Url: https://codereview.chromium.org/2400543002
Cr-Commit-Position: refs/heads/master@{#423775}