Remove some dead code in devtools for old loading path.

Bug: 934009
Change-Id: I859a008b9a68313d3d0479225d20b2b23acf4de4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1738667
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Auto-Submit: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684440}
7 files changed