GitLab

Convert error page tests to always use URLLoaderInterceptor.

The test class now works with frame requests when the network service is disabled.

Bug: 776589
Change-Id: Ieae2c903860e5263aa73fc3f3521de9f53b0eb4d
Reviewed-on: https://chromium-review.googlesource.com/1038621Reviewed-by: Doug Turner <dougt@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555401}