Normalize a couple of print preview browser tests.

Normalize a couple of print preview browser tests.

PrintWebViewHelperTest.PrintWithIframe document.write()s into
a loaded iframe without a document.close(). This blocks the load event in the parent frame and will soon block load completion notifications.

BlockScriptInitiatedPrinting operates on an initial empty document, which can have strange effects. Load one of the html strings provided in that file, just so we have a real document to work with.

BUG=

Committed: https://crrev.com/87390022e9c1c9bf5e90e062184acce674233252
Cr-Commit-Position: refs/heads/master@{#294736}

[Nate Chapin, 2014-09-12 22:15:37]

japhet@chromium.org changed reviewers:
+ vitalybuka@chromium.org

[Nate Chapin, 2014-09-12 22:15:38]

A couple of quirks in print_web_view_helper_browsertest.cc that I found as a
result of working on https://codereview.chromium.org/561813003/. PTAL :)

[Vitaly Buka (NO REVIEWS), 2014-09-13 05:55:14]

The CQ bit was checked by vitalybuka@chromium.org

[Vitaly Buka (NO REVIEWS), 2014-09-13 05:55:14]

lgtm

[commit-bot: I haz the power, 2014-09-13 05:56:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/568933002/1

[commit-bot: I haz the power, 2014-09-13 06:53:31]

Committed patchset #1 (id:1) as a9f14740b2a50376c2bb85fbc1761e85362f8d46

[commit-bot: I haz the power, 2014-09-13 06:56:14]

Patchset 1 (id:??) landed as
https://crrev.com/87390022e9c1c9bf5e90e062184acce674233252
Cr-Commit-Position: refs/heads/master@{#294736}