Report resource type in resource starts

Report resource type in DidStartResponse. This will be used by
MetricsRenderFrameObserver to distinguish frame requests.

Bug: 836029
Change-Id: I9e5cc9ec220286dd15b110114c624c81afe60e13
Reviewed-on: https://chromium-review.googlesource.com/1123374
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: rajendrant <rajendrant@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572093}
6 files changed