GitLab

We don't need to wrap the data with WebThreadSafeData here. Just use a
pair of const char* and size_t.

This is Chromium side CL

Blink side CL: https://codereview.chromium.org/611923002/

R=yhirano,jam
BUG=417093

Review URL: https://codereview.chromium.org/610333002

Cr-Commit-Position: refs/heads/master@{#300064}