Revert "Shell EOF derps : Chromium prebuilt"

This reverts commit 3feb02eb8ad576c9ea7ae17dfe8f1142318d41d2.
Revert "Prebuilt chromium: update script for lollipop"

This reverts commit 503be39376540aa510faf14d3eed201b609defbd.
Revert "vendor/omni: Fix-ups for prebuilt Chromium"

This reverts commit 6ea61a3aeb81f98567a6cc3a156761d9c2cc4bb8.
Revert "vendor/omni: Add chromium_prebuilt.sh"

This reverts commit 4c86a55ccd2ac65a53611d8c80f8fcfc810b0cb6.