ResourceLoadScheduler: add a sub-frame specific param to limit requests

The first results from beta channel trial reveals typical outstanding
request numbers of sub-frames are very different from one of the main
frame. It suggests us to have different limits for each, e.g. more
aggressive limit for sub-frames.

This patch adds a separate trial parameter to set the outstanding
limit for sub-frames so that we can study performance difference from
field trials of having different limits for the main frame and others.

Bug: 768325
Change-Id: I82e8169a00acfa71a8895869621f7c1333902a85
Reviewed-on: https://chromium-review.googlesource.com/681098
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505993}
2 files changed