Introduce static content getter for Tooltip
Introduce static content getter for Tooltip

This allows us to migrate all getters of `title` on HTMLElement
to use the static method.

R=993fcadce4d04090da2fefd557a0995e7966c8d5@chromium.org

Bug: 1150762
Change-Id: Ia376a92337af4e45de36342160ce9397374cadb8
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2556687
Auto-Submit: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Commit-Queue: Jack Franklin <993fcadce4d04090da2fefd557a0995e7966c8d5@chromium.org>
Reviewed-by: Jack Franklin <993fcadce4d04090da2fefd557a0995e7966c8d5@chromium.org>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend