Remove Text.proto.select from DOMExtension
Remove Text.proto.select from DOMExtension

There are no references to it in the codebase, and nothing breaks when I
remove it. Therefore I think whatever relied upon this has been removed
and therefore we can remove the method too.

Bug: 1050549
Change-Id: Ic75a11fc31169a985f86edd1b4d728a0ccc7b380
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3966444
Commit-Queue: Simon Zünd <38944668e9e2ca98ccd0275b53370f90fa55c113@chromium.org>
Reviewed-by: Simon Zünd <38944668e9e2ca98ccd0275b53370f90fa55c113@chromium.org>
Auto-Submit: Jack Franklin <993fcadce4d04090da2fefd557a0995e7966c8d5@chromium.org>

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