Binary size tool: Don't escape text that won't be parsed.

Only text that will be sent through an HTML parser needs to be parsed.
Escaping more than that results in & and < and similar in the
output.

R=andrewhayden@chromium.org

BUG=412708

Review URL: https://codereview.chromium.org/562623002

Cr-Commit-Position: refs/heads/master@{#294176}
1 file changed