This is the second step of migrating to our new XSRF token format. The
first step ([] made validate() start accepting new tokens
(basically, dual-read). This step cuts over our "writing" to write the
new token format. The third and final step will drop support for
validating the old token format (back to single-read). We'll do that
in a subsequent push so that we don't invalidate all the current XSRF
tokens that people might have in their browsers.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=149790648
2353bcd8c5