Support international characters in animation worklets.

Code in cc/ is not permitted to use wtf::String. Thus, we perform conversions between wtf::String and std::string.  The later is not aware of encodings.  This is OK provided a consistent encoding is used for round tripping, where the encoding supports the set of allowed characters.  The UTF-8 encoding is adequate for this task and supported by wtf::String.

Bug: 940493
Change-Id: Ie2b994412f502ea11df06713439b8cf8ffedc885
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1524087
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Kevin Ellis <kevers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641278}
4 files changed