Google Drive is Google's file sync app that lets you store all of your files online alongside your Google Docs documents, and keep them synced with all of your devices.
Surface the brand decision and approved brief with each asset.
Your reviewers see the brief beside the asset, with the brand decision they need to make clearly stated.
Place the current campaign draft in your approval task.
Your brand reviewer gets the current campaign draft and the decision needed together on the review task.