Internal Google bug: http://b/27955065

ENV :
Build [gmail_fe_160331.00_p0]
Chrome Pixel / Chrome 51 Dev
Account : terer.clean.1qa4@gmail.com, tererprod6@gmail.com

Repro Steps:
1. Open a conversation with attachment.
2. Long press the attachment to view the download, save to drive buttons
3. Tap on download button to download attachment
4. Tab on Inbox label or any other part of the Gmail UI

Expected:
3. Attachment gets downloaded
4. Inbox gets loaded or the corresponding UI is rendered

Actaul:
Nothing happens. UI is freezed.
UI does not respond even after reloading the tab / browser.

Chrome 49: OK
Chrome 50(beta): OK
Chrome 51(dev): FAIL