[Password Generation] Require full form match to allow generation

[Password Generation] Require full form match to allow generation

Previously as long as the origin of the form recieved from Autofill matched
the form detected by heuristics (i.e. the page hadn't navigated before parsing
the server response), the first form on the page that matched local heuristics
was assumed to be the account creation form.

BUG=447484
Committed: https://crrev.com/7a4fa8b14caa96d30b4966f5bc9c132f9fcabfd5
Cr-Commit-Position: refs/heads/master@{#310788}

[Garrett Casto, 2015-01-09 08:18:36]

gcasto@chromium.org changed reviewers:
+ vabr@chromium.org

[vabr (Chromium), 2015-01-09 08:55:35]

lgtm

[Garrett Casto, 2015-01-09 17:12:31]

The CQ bit was checked by gcasto@chromium.org

[commit-bot: I haz the power, 2015-01-09 17:12:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/845693002/1

[commit-bot: I haz the power, 2015-01-09 17:24:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-09 17:25:01]

Patchset 1 (id:??) landed as
https://crrev.com/7a4fa8b14caa96d30b4966f5bc9c132f9fcabfd5
Cr-Commit-Position: refs/heads/master@{#310788}