Fix Browser Controller to not reuse iFrames, which can sometimes cause bad state to be left between…

Fix Browser Controller to not reuse iFrames, which can sometimes cause bad state to be left between tests.

BUG=
R=jmesserly@google.com

Committed: https://code.google.com/p/dart/source/detail?r=35157

[Emily Fortuna, 2014-04-17 22:21:35]

This I believe should fix the "flaky" issue on IE 11. Turns out it was a problem
with the browser controller itself.

[Jennifer Messerly, 2014-04-17 22:29:05]

https://codereview.chromium.org/241783003/diff/1/tools/testing/dart/browser_c...
File tools/testing/dart/browser_controller.dart (right):

https://codereview.chromium.org/241783003/diff/1/tools/testing/dart/browser_c...
tools/testing/dart/browser_controller.dart:1378:
embedded_iframe.parentNode.removeChild(embedded_iframe);
you might need to remove it from
https://developer.mozilla.org/en-US/docs/Web/API/Window.frames too. not 100%
sure, but it'd be worth checking that list isn't getting bigger.

https://codereview.chromium.org/241783003/diff/1/tools/testing/dart/browser_c...
tools/testing/dart/browser_controller.dart:1502: <iframe
id="embedded_iframe"></iframe>
one idea here would be to make this a div and add the iframe as a child. but I
dunno if anywhere else queries IDs.

[Jennifer Messerly, 2014-04-17 22:51:11]

LGTM

[Emily Fortuna, 2014-04-17 22:56:14]

Committed patchset #2 manually as r35157 (presubmit successful).

[ricow1, 2014-04-18 08:11:04]

Just out of curiosity:
How can this ever have an impact on the second test, i.e., what steps will
reproduce this behavior? Could you share the debugging info you got from the
bot?
Additionally, what kind of impact does this have on our cycle times. I assume
that especially when creating new windows you will have an added overhead

[Jennifer Messerly, 2014-04-18 20:17:30]

On 2014/04/18 08:11:04, ricow1 wrote:
> Just out of curiosity:
> How can this ever have an impact on the second test, i.e., what steps will
> reproduce this behavior? Could you share the debugging info you got from the
> bot?
> Additionally, what kind of impact does this have on our cycle times. I assume
> that especially when creating new windows you will have an added overhead


Context here: there's a tricky IE problem, we don't know what's causing it. It
could even be a bug in IE 11, like memory corruption, we don't know yet. One
guess I had is maybe discarding & creating the <iframe> node, instead of just
mutating the src, would help. I don't think it would affect cycle time since
it's just 1 node. In any case, it didn't help so I think Emily is/has reverted.