Dropbox — terms can be found here:
“Your Stuff & Your Privacy: By using our Services you provide us with information, files, and folders that you submit to Dropbox (together, “your stuff”). You retain full ownership to your stuff. We don’t claim any ownership to any of it. These Terms do not grant us any rights to your stuff or intellectual property except for the limited rights that are needed to run the Services, as explained below.”
Google Drive — terms can be found here:
“Your Content in our Services: When you upload or otherwise submit content to our Services, you give Google (and those we work with) a worldwide licence to use, host, store, reproduce, modify, create derivative works (such as those resulting from translations, adaptations or other changes that we make so that your content works better with our Services), communicate, publish, publicly perform, publicly display and distribute such content.
The rights that you grant in this licence are for the limited purpose of operating, promoting and improving our Services, and to develop new ones. This licence continues even if you stop using our Services (for example, for a business listing that you have added to Google Maps).”