[GN] Remove a duplication of a source type check

There was a duplication of the source type checking. It may lead
errors when a type set will be changed for a language.

R=dpranke@chromium.org

Bug: None
Change-Id: Ieab8885899446e625cfe20c1650418a085b937ee
Reviewed-on: https://chromium-review.googlesource.com/702414
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#506763}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 844a031c63c6ec1123da1b5b0caa97958679ddf5
1 file changed
tree: 9e23c766348deea207045a19ac82f8aba2ab6f8f
  1. tools/