Chrome OS version: 61.0.3163.72, beta build
Platform version: 9765.49.0, beta channel sentry device
M-61 build

Steps To Reproduce:
(1) Try to fill the entire space on Google Drive (may be upto 100KB remaining).
(2) Prepare an SD card with photos in DCIM/ folder, that exceeds the available space of Google Drive.
(3) Insert the SD card. Goto DCIM folder. Cloud Backup details dialog pops up.
(4) Click "BACK UP" button.
(5) Observe that import and sync operation finishes.
(6) There is no warning/ error message displayed to the user.
(7) If you check GDrive>Chrome OS Cloud backup folder, files are not copied.
(8) But, navigate to SD card>DCIM folder, status of all files shows as synced with GDrive. Also, Cloud import option as 'All backed up'. This is a misleading info to the user.

Expected Result:
A warning message/ notification should be displayed indication back up is failed due to insufficient space in GDrive. Import and sync operation must not progress.

Attachments indicate that even though in less GDrive space, status of DCIM folder displays as synced with GDrive.
 

Deleted: Screenshot 2017-08-30 at 17.28.58.png 113 KB

	Screenshot 2017-08-30 at 17.28.58.png 113 KB View Download

Deleted: Screenshot 2017-08-30 at 17.29.16.png 164 KB

	Screenshot 2017-08-30 at 17.29.16.png 164 KB View Download