Code: void WebRuntimeFeatures::EnableRequireCSSExtensionForFile(bool enable) {
  RuntimeEnabledFeatures::SetRequireCSSExtensionForFileEnabled(enable);
}

Vulnerability Type: 
CWE ID: CWE-254
Summary: Insufficient file type enforcement in Blink in Google Chrome prior to 69.0.3497.81 allowed a remote attacker to obtain local file data via a crafted HTML page.
Commit Message: Remove RequireCSSExtensionForFile runtime enabled flag.

The feature has long since been stable (since M64) and doesn't seem
to be a need for this flag.

BUG=788936

Change-Id: I666390b869289c328acb4a2daa5bf4154e1702c0
Reviewed-on: https://chromium-review.googlesource.com/c/1324143
Reviewed-by: Mike West <mkwst@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607329}