Version: 56.0.2905.0
OS: Windows, Linux (probably all)

What steps will reproduce the problem?
(1) Visit http://csreis.github.io/tests/window-open.html
(2) Click "Open simple window"
(3) In the new tab, go to a cross-process slow URL (e.g., http://127.0.0.1:8080/slow?5 when running testserver.py)
(4) Go back to simple.html
(5) Clear browsing data to clear your cache
(6) Select the "Simple" text on the page
(7) Go forward (Alt+Right) and immediately start dragging the selected text.  Wait for the new page to commit and drop the text.  (Surprisingly, this works-- if there's a form on the page, you can drop the text into it.  Appears to work in the same-process case as well.)
(8) Go back.

What is the expected output?

You should be able to select text or use the context menu on simple.html.

What do you see instead?

All input events are ignored.

The page is not unresponsive (e.g., in DevTools), though, and the original tab still responds to input.  We don't get any hang events.  The old RenderView is probably just in a bad state, blocked on the unfinished drag.

Maybe we should be resetting some drag state when swapping out?

(I found this while trying to find repro steps for https://codereview.chromium.org/2457503002 for issue 615090.)