Verify other multi-frame concerns in SaveCrossSitePage test.

Verify other multi-frame concerns in SaveCrossSitePage test.

After the changes the test:

- Continues to test cross-site / multiple-renderer-processes case.

- Starts to verify that frame links got correctly replaced with
  local paths (this uses a separate code path from replacing links
  of other, non-frame savable resources).

- Starts to test that deduplication of savable resources happens across frames
  (deduplication got moved into the browser process in
  https://chromium.googlesource.com/chromium/src/+/6af746b740287560dbc9e85d22738000bc72b521).

BUG=526786
Committed: https://crrev.com/4bfb141876bc334c47688ee74d710692eed3ec31
Cr-Commit-Position: refs/heads/master@{#351133}

[Łukasz Anforowicz, 2015-09-23 20:07:28]

lukasza@chromium.org changed reviewers:
+ rdsmith@chromium.org

[Łukasz Anforowicz, 2015-09-23 20:07:29]

Randy, could you please take a look? (small, test-only CL)

[Łukasz Anforowicz, 2015-09-25 18:14:00]

lukasza@chromium.org changed reviewers:
+ asanka@chromium.org

[Łukasz Anforowicz, 2015-09-25 18:14:00]

Asanka, could you please take a look?  (I believe Randy is out of office for a
few days).

[Randy Smith (Not in Mondays), 2015-09-28 00:38:14]

LGTM (sorry, you were quite right, I was OOO).

[Łukasz Anforowicz, 2015-09-28 16:02:53]

The CQ bit was checked by lukasza@chromium.org

[commit-bot: I haz the power, 2015-09-28 16:04:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1362973003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1362973003/1

[commit-bot: I haz the power, 2015-09-28 20:52:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-28 20:53:41]

Patchset 1 (id:??) landed as
https://crrev.com/4bfb141876bc334c47688ee74d710692eed3ec31
Cr-Commit-Position: refs/heads/master@{#351133}