Allow exntesion resources to be loaded into DevTools front-end frame

Allow exntesion resources to be loaded into DevTools front-end frame 

Patch from caseq@chromium.org
R=Erik Kay
BUG=none
TEST=none

[caseq, 2010-08-09 16:57:25]

Cris, you recently added code in extension_protocols.cc that prevents an
extension resource from being loaded into frames that are not on this
extension's URL permission list. This interferes with the way we're implementing
DevTools extensions (these should be loaded as iframes into DevTools front-end
page, but should not have content script permissions to chrome://devtools). I'd
like to add an explicit exception in your code for our case.

Erik, I'd like to add a special permission for DevTools extensions. It is
maintained implicitly by manifest parsing code (so I'm not adding it to
Extension::kPermissionNames, as we don't expect to see it in the manifest). So
far we just use it to check for the case I described above, but I thought it
would be generally useful in the future to warn user when new extension is
installed or when an upgraded extension has elevated privileges.

[Cris Neckar, 2010-08-09 17:00:06]

An exception sounds fine to me. Sorry for the breakage.

On 2010/08/09 16:57:25, caseq wrote:
> Cris, you recently added code in extension_protocols.cc that prevents an
> extension resource from being loaded into frames that are not on this
> extension's URL permission list. This interferes with the way we're
implementing
> DevTools extensions (these should be loaded as iframes into DevTools front-end
> page, but should not have content script permissions to chrome://devtools).
I'd
> like to add an explicit exception in your code for our case.
> 
> Erik, I'd like to add a special permission for DevTools extensions. It is
> maintained implicitly by manifest parsing code (so I'm not adding it to
> Extension::kPermissionNames, as we don't expect to see it in the manifest). So
> far we just use it to check for the case I described above, but I thought it
> would be generally useful in the future to warn user when new extension is
> installed or when an upgraded extension has elevated privileges.

[Aaron Boodman, 2010-08-09 22:18:53]

I think we can just allow the dev tools to load any extension resource. There is
no need to lock it down to just the dev tools extension. That should simplify
things (it would only require a change to extension_protocols.cc).

[caseq, 2010-08-10 08:06:56]

On 2010/08/09 22:18:53, Aaron Boodman wrote:
> I think we can just allow the dev tools to load any extension resource. There
is
> no need to lock it down to just the dev tools extension. That should simplify
> things (it would only require a change to extension_protocols.cc).

Indeed -- I realized we have at list one other legit case for loading extension
resources into DevTools, which is displaying image resources in Content tab of
the Resource pane. I think we will still want devtools permissions eventually
(for notifying users), but that would be a separate change.

[Erik does not do reviews, 2010-08-10 14:57:18]

LGTM

[Aaron Boodman, 2010-08-10 18:05:35]

The original change also broke the app launcher UI in the NTP. It loads
extension resources from chrome://newtab/. I'm going to change this logic to
just always allow from chrome://.

[loislo, 2010-08-11 07:42:21]

2caseq: could you please rebase the patch