Disable the new tab-loading animation

Makes sure that a lot of animation-related code is bypassed when the
new-tab-animation flag is off. This should hopefully fix a couple of
performance regressions that have not yet been root caused so that they
don't go out with M72.

Bug: chromium:912328, chromium:905745, chromium:905918, chromium:910265
Change-Id: Id3f131db427eb3ee1618d6c9683fd5e47dc134e8
Reviewed-on: https://chromium-review.googlesource.com/c/1364212
Reviewed-by: Sidney San Martín <sdy@chromium.org>
Commit-Queue: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614199}
3 files changed