Implement fast path in UTF8ToUTF16 for pure ASCII strings
Blink WebString::fromUTF8 are marginally faster than UTF8ToUTF16 on
pure ASCII input because they have a fast path for this case. Implement
the same thing for base::UTF8ToUTF16
DoIsStringASCII is now a port of charactersAreAllASCII from Blink.
BUG=391492
R=brettw@chromium.org, torne@chromium.org
Review URL: https://codereview.chromium.org/543043002
Cr-Commit-Position: refs/heads/master@{#297158}
CrOS-Libchrome-Original-Commit: 6f500092b9396517a40fdf1ca6a5199738e673e9
4 files changed