goog.dom.createDom is about to support only the members of
goog.dom.TagName to improve the precision of its return type. This CL
prepares for that.
CL automatically created by:
replace_string --pcre
(\.createDom\(\s*)\'([a-z0-9]+)'
$1goog.dom.TagName.$2
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=128802686