Add FormData::is_action_empty.

In case of a form action is absent, FormData::action is set to origin.
That makes it impossible to check whether FormData has an empty action.
And it's used for detection of submission success in Password Manager.
This CL fixed that.

Bug: 1008798
Change-Id: Ic44aaf6ef94df6766fe7eddccbe14a2b030974a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1832818
Reviewed-by: Emily Stark <[email protected]>
Reviewed-by: Dominic Battré <[email protected]>
Commit-Queue: Vadym Doroshenko <[email protected]>
Cr-Commit-Position: refs/heads/master@{#705890}
8 files changed