You can find this sentence: "Your app can be a file provider too!" in slide 23 of This lecture: Contracts and Pickers: Building Apps that Work Together on Windows | Build 2014 | Channel 9
Also the slide show clearly shows that OneDrive will be integrated into file picker, which is missing in current version of emulator ( http://forums.windowscentral.com/windows-phone-8-1/273064-file-picker-screenshots.html ) maybe they need to update the OneDrive app?
So we can expect OneDrive and other cloud storage services integration in the file picker.
Also the slide show clearly shows that OneDrive will be integrated into file picker, which is missing in current version of emulator ( http://forums.windowscentral.com/windows-phone-8-1/273064-file-picker-screenshots.html ) maybe they need to update the OneDrive app?
So we can expect OneDrive and other cloud storage services integration in the file picker.