GTTF: Make wtf_unittests and blink_platform_unittests support new test launcher.

Note that it's still behind a flag, --brave-new-test-launcher

This depends on https://codereview.chromium.org/89903003 Chromium-side

BUG=290597, 236893

Review URL: https://codereview.chromium.org/89753002

git-svn-id: svn://svn.chromium.org/blink/trunk@162745 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Have DOMWindow name getter / setter deal with AtomicStrings

Have DOMWindow name getter / setter deal with AtomicStrings instead of Strings.
We use an AtomicString for the window name internally so this avoids constructing
a String uselessly and then converting it to an AtomicString.

R=abarth
BUG=323739

Review URL: https://codereview.chromium.org/89943002

git-svn-id: svn://svn.chromium.org/blink/trunk@162746 bbb929c8-8fbe-4397-9dbb-9b2b20218538