Add /cross-site/ request handler to testserver.py

Add /cross-site/ request handler to testserver.py

Adding this handler will make authoring tests which exercise cross-site navigations much easier. This is harder in the current codebase, because testserver runs on a random port each time it is ran which requires boilerplate code in each test that needs it. Instead of computing the real URL in C++ code, just navigate using "/cross-site/hostname/path/and/more" and the server will redirect to the new host.
This requires browser tests to map all hosts to localhost, which is done by adding 'host_resolver()->AddRule("*", "127.0.0.1");' to the beginning of the test.

BUG=418236
Committed: https://crrev.com/14c66460be23532452ae32f3546e5578ab48c590
Cr-Commit-Position: refs/heads/master@{#297182}

[nasko, 2014-09-26 20:44:54]

nasko@chromium.org changed reviewers:
+ phajdan.jr@chromium.org

[nasko, 2014-09-26 20:44:54]

Hi Paweł,
Can you review this CL for me?
Thanks in advance,
Nasko

[nasko, 2014-09-26 20:46:48]

Adding site-isolation-dev@

[Paweł Hajdan Jr., 2014-09-26 22:10:14]

Will this be used in src/net or in some layer above like src/chrome?

For the latter, I'd strongly urge you to use EmbeddedTestServer instead. The
python test server has known flakiness issues
(https://code.google.com/p/chromium/issues/detail?id=96594).

[nasko, 2014-09-26 22:29:56]

On 2014/09/26 22:10:14, Paweł Hajdan Jr. wrote:
> Will this be used in src/net or in some layer above like src/chrome?
> 
> For the latter, I'd strongly urge you to use EmbeddedTestServer instead. The
> python test server has known flakiness issues
> (https://code.google.com/p/chromium/issues/detail?id=96594).

This will be used in src/content. I will add the same type of support to
EmbeddedTestServer as well, but it will be in a separate patch. Existing tests
use testserver.py, so I want to cover them as well, hence the need for this CL.

[Paweł Hajdan Jr., 2014-09-26 23:14:44]

On 2014/09/26 22:29:56, nasko wrote:
> This will be used in src/content. I will add the same type of support to
> EmbeddedTestServer as well, but it will be in a separate patch. Existing tests
> use testserver.py, so I want to cover them as well, hence the need for this
CL.

I know this is balancing on close to the scope limits of the task you're working
or, but could you consider converting the affected tests to EmbeddedTestServer?

Especially since you're working on improving this part of our testing
infrastructure, I think it's really worth it. Given the above bug is known at
least since 2011 and nobody found a fix for it, I'd prefer to avoid it
altogether.

Adding support for /cross-site/ to the known-unreliable test server might
prolong the use of it by the tests you'd be working on.

[nasko, 2014-09-26 23:41:27]

On 2014/09/26 23:14:44, Paweł Hajdan Jr. wrote:
> On 2014/09/26 22:29:56, nasko wrote:
> > This will be used in src/content. I will add the same type of support to
> > EmbeddedTestServer as well, but it will be in a separate patch. Existing
tests
> > use testserver.py, so I want to cover them as well, hence the need for this
> CL.
> 
> I know this is balancing on close to the scope limits of the task you're
working
> or, but could you consider converting the affected tests to
EmbeddedTestServer?

The cost of this CL is almost trivial, whereas the cost of moving over tests to
EmbeddedTestServer is not.

> Especially since you're working on improving this part of our testing
> infrastructure, I think it's really worth it. Given the above bug is known at
> least since 2011 and nobody found a fix for it, I'd prefer to avoid it
> altogether.

What but is known since 2011?
 
> Adding support for /cross-site/ to the known-unreliable test server might
> prolong the use of it by the tests you'd be working on.

Not adding support for might means less test coverage. If you prefer, I can also
file a bug to remove this later once code has migrated over to
embedded_test_server().

[Paweł Hajdan Jr., 2014-09-29 09:01:47]

LGTM just to avoid blocking you

Please be aware of https://code.google.com/p/chromium/issues/detail?id=96594 I
mentioned before. You're entering known flaky territory, and EmbeddedTestServer
is the recommended known-to-work replacement (only net_unittests is not using it
because we'd like to test it using an independent implementation of a network
stack). Please consider trying to perform the conversion and it should be easy.

Again, you're entering known flaky territory.

[nasko, 2014-09-29 15:13:50]

On 2014/09/29 09:01:47, Paweł Hajdan Jr. wrote:
> LGTM just to avoid blocking you
> 
> Please be aware of https://code.google.com/p/chromium/issues/detail?id=96594 I
> mentioned before. You're entering known flaky territory, and
EmbeddedTestServer
> is the recommended known-to-work replacement (only net_unittests is not using
it
> because we'd like to test it using an independent implementation of a network
> stack). Please consider trying to perform the conversion and it should be
easy.
> 
> Again, you're entering known flaky territory.

Thank you for understanding. I will rip this out as soon as the
EmbeddedTestServer change is complete and all tests are migrated over.

[nasko, 2014-09-29 15:13:56]

The CQ bit was checked by nasko@chromium.org

[commit-bot: I haz the power, 2014-09-29 15:14:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/612533002/1

[commit-bot: I haz the power, 2014-09-29 15:53:27]

Committed patchset #1 (id:1) as 204b30b8848a01b779fb60c389898e26fcc4a5ad

[commit-bot: I haz the power, 2014-09-29 15:54:14]

Patchset 1 (id:??) landed as
https://crrev.com/14c66460be23532452ae32f3546e5578ab48c590
Cr-Commit-Position: refs/heads/master@{#297182}