Use a direct include of strings headers in testing/, third_party/, tools/.

BUG=247723
TEST=none
TBR=ben@chromium.org

Review URL: https://chromiumcodereview.appspot.com/15851009

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 66cbe221405716e58c9e22d877b3c58fcb8ed656
3 files changed