Better distinguish between blocked and empty pages in XSS filter tests.

Better distinguish between blocked and empty pages in XSS filter tests.

We currently detect the XSSAuditor's fully-blocked frames by the inability
of a parent frame to access their contents due to the cross-origin "data:," URL
they are redirected to as a result of the block. An example of this technique
is the "cross origin frame" console message present in many CSP tests.

Before we can improve the mechanism by which fully-blocked frames are handled,
we need to stop relying on this side-effect.  Instead, it is better to dump
all child frames, and see if they have partial contents.

But to do this we must ensure that all tests put some minimal content
into the frame, otherwise a blocked frame and an empty frame produce identical
output.  We do this in the echo-intertag.pl file.

This was split off from a forthcoming CL to reduce the file count in that CL.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178939

[Tom Sepez, 2014-07-24 23:33:20]

Mike, please review.  Thanks!

[Mike West, 2014-07-25 08:39:53]

LGTM!

It took me a little while to find the actual change: would you mind noting that
the .pl file is the important bit in the change description?

It would also be worthwhile to add "Better distinguish between blocked and empty
pages in XSS filter tests." as a line at the top of the description so that
'git' displays the CL nicely.

[Tom Sepez, 2014-07-25 15:59:47]

The CQ bit was checked by tsepez@chromium.org

[Tom Sepez, 2014-07-25 16:00:04]

On 2014/07/25 08:39:53, Mike West wrote:
> LGTM!
> 
> It took me a little while to find the actual change: would you mind noting
that
> the .pl file is the important bit in the change description?
> 
> It would also be worthwhile to add "Better distinguish between blocked and
empty
> pages in XSS filter tests." as a line at the top of the description so that
> 'git' displays the CL nicely.

Done.

[commit-bot: I haz the power, 2014-07-25 16:00:14]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tsepez@chromium.org/420603003/40001

[commit-bot: I haz the power, 2014-07-25 16:04:01]

Change committed as 178939