Changing third-party cookie blocking: strict by default.

Changing third-party cookie blocking: strict by default.

The current behavior of third-party cookie blocking blocks setting third-party
cookies, but not reading those that exist. A cookie set during a direct visit to
`example.com` would be sent with requests to `example.com` in the future, even
when `example.com` wasn't the first-party. The `kBlockReadingThirdPartyCookies`
command-line flag changed this behavior to block all access to third-party
cookies.

This CL makes strict blocking the default behavior, removes the command-line
flag, and changes the text of the preference UI checkbox.

It might also be possible to remove the `BLOCK_SETTING_THIRD_PARTY_COOKIES`
cookie policy entirely; I didn't see it used anywhere other than for this
preference, but need to clarify that before dropping it as well.

BUG=98241
TEST=unit_tests

[Mike West, 2011-09-28 07:41:58]

Hi Jochen, Bernhard:

As discussed this morning, I think it's worthwhile to try this out on Canary for
a bit to see if things explode.

-Mike

[Mike West, 2011-09-28 07:44:07]

Aaaaand it looks like I misunderstood the conclusion of our conversation,
Jochen. :) Ignore this CL, I'll work on converting
`kBlockReadingThirdPartyCookies` to a pref.

[jochen (gone - plz use gerrit), 2011-09-28 07:46:48]

I think it would be better to just make the flag on by default for now, instead
of ripping out the whole code path.

In order to not mess with the UI too much, I also wouldn't change the strings
for now

http://codereview.chromium.org/8051030/diff/1/chrome/browser/content_settings...
File chrome/browser/content_settings/host_content_settings_map.cc (right):

http://codereview.chromium.org/8051030/diff/1/chrome/browser/content_settings...
chrome/browser/content_settings/host_content_settings_map.cc:212:
net::StaticCookiePolicy::BLOCK_ALL_THIRD_PARTY_COOKIES);
I think it would be preferable to keep a pref so you can chose which behavior
you want using an extension API

http://codereview.chromium.org/8051030/diff/1/chrome/browser/content_settings...
chrome/browser/content_settings/host_content_settings_map.cc:597:
net::StaticCookiePolicy::BLOCK_ALL_THIRD_PARTY_COOKIES);
we don't write this pref key, so it should never be
BLOCK_ALL_THIRD_PARTY_COOKIES

[Mike West, 2011-09-28 09:46:34]

As discussed, I'll put this to the side for the moment in favor of forcing the
command-line switch on for a few Canary releases. That CL is
http://codereview.chromium.org/8060030/.

Thanks!

On 2011/09/28 07:46:48, jochen wrote:
> I think it would be better to just make the flag on by default for now,
instead
> of ripping out the whole code path.
> 
> In order to not mess with the UI too much, I also wouldn't change the strings
> for now
> 
>
http://codereview.chromium.org/8051030/diff/1/chrome/browser/content_settings...
> File chrome/browser/content_settings/host_content_settings_map.cc (right):
> 
>
http://codereview.chromium.org/8051030/diff/1/chrome/browser/content_settings...
> chrome/browser/content_settings/host_content_settings_map.cc:212:
> net::StaticCookiePolicy::BLOCK_ALL_THIRD_PARTY_COOKIES);
> I think it would be preferable to keep a pref so you can chose which behavior
> you want using an extension API
> 
>
http://codereview.chromium.org/8051030/diff/1/chrome/browser/content_settings...
> chrome/browser/content_settings/host_content_settings_map.cc:597:
> net::StaticCookiePolicy::BLOCK_ALL_THIRD_PARTY_COOKIES);
> we don't write this pref key, so it should never be
> BLOCK_ALL_THIRD_PARTY_COOKIES