Make FrameTree::uniqueName() more unique.

Make FrameTree::uniqueName() more unique.

Currently, it only guarantees no two siblings have the same unique name. This
patch tries much harder to guarantee that no two frames in the same page have
the same unique name.

BUG=352651
TEST=http/tests/history/frameset-repeated-name.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169764

[abarth-chromium, 2014-03-21 00:25:18]

lgtm

[Nate Chapin, 2014-03-21 16:17:22]

The CQ bit was checked by japhet@chromium.org

[commit-bot: I haz the power, 2014-03-21 16:17:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/japhet@chromium.org/207143002/1

[commit-bot: I haz the power, 2014-03-21 16:53:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-21 16:53:39]

Try jobs failed on following builders:
  tryserver.blink on mac_blink_rel

[Nate Chapin, 2014-03-21 17:21:17]

The CQ bit was checked by japhet@chromium.org

[commit-bot: I haz the power, 2014-03-21 17:21:25]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/japhet@chromium.org/207143002/20001

[commit-bot: I haz the power, 2014-03-21 17:53:59]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-21 17:54:00]

Try jobs failed on following builders:
  tryserver.blink on win_blink_compile_dbg

[Nate Chapin, 2014-03-21 17:54:32]

The CQ bit was checked by japhet@chromium.org

[commit-bot: I haz the power, 2014-03-21 17:54:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/japhet@chromium.org/207143002/20001

[commit-bot: I haz the power, 2014-03-21 18:16:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-21 18:16:29]

Try jobs failed on following builders:
  tryserver.blink on linux_blink_dbg

[Nate Chapin, 2014-03-21 18:18:43]

The CQ bit was checked by japhet@chromium.org

[commit-bot: I haz the power, 2014-03-21 18:18:47]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/japhet@chromium.org/207143002/20001

[commit-bot: I haz the power, 2014-03-21 19:27:46]

Change committed as 169764