Freeze a page quickly after backgrounded.

Change-Id: I2d9014f6951657d9bf09530e70546266d98b8852
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1417430
Reviewed-by: François Doray <fdoray@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/master@{#649423}
12 files changed