GN: Mark dl sourceset as non-chromium code to silence compiler warnings

Warnings show when target_cpu="arm64"

BUG=568883
NOTRY=true
NOPRESUBMIT=true
R=rtoy@google.com

Review URL: https://codereview.webrtc.org/1520893002 .
1 file changed
tree: 03b7a8dd9183fefdd2c99d72acc1ca0fa277f171
  1. dl/
  2. codereview.settings
  3. LICENSE
  4. OWNERS
  5. README.chromium