Optionally support relative include paths in cpp_checker.py

Optionally support relative include paths in cpp_checker.py

This is needed to support full DEPS include_rules under pdfium,
where relative pathnames are used exclusively for include directives.

This will be controlled by the --resolve-dotdot command line flag,
since we don't want to encourage the practice.

R=brettw@chromium.org

Committed: 46ce8cb60364e9e0b21a81136c7debdddfd063a8

[Tom Sepez, 2015-06-05 01:26:28]

tsepez@chromium.org changed reviewers:
+ brettw@chromium.org

[Tom Sepez, 2015-06-05 01:26:29]

Brett, for review.  This would let the tool be used against our PDFium codebase.
 Thanks.

[brettw, 2015-06-05 17:58:03]

Can this have more documentation on the details of exactly how it works? For
example:

When it sees "../" where is the current directory taken from? The file that
includes it?

We should also note that just saying "foo/bar.h" or even "./foo/bar.h" where foo
is a subdirectory of the current one still doesn't work. I might assume this
would work given the name of the feature.

[Tom Sepez, 2015-06-05 18:33:33]

On 2015/06/05 17:58:03, brettw wrote:
> Can this have more documentation on the details of exactly how it works? For
> example:
> 
> When it sees "../" where is the current directory taken from? The file that
> includes it?
Yes, exactly.

> 
> We should also note that just saying "foo/bar.h" or even "./foo/bar.h" where
foo
> is a subdirectory of the current one still doesn't work. I might assume this
> would work given the name of the feature.
how about --allow-dotdot, then?

[Tom Sepez, 2015-06-05 18:50:02]

See PS#4.

[Lei Zhang, 2015-06-05 19:04:19]

Have we considered the alternative to this CL - stop using relative include
paths in pdfium?

[Tom Sepez, 2015-06-05 19:12:26]

On 2015/06/05 19:04:19, Lei Zhang wrote:
> Have we considered the alternative to this CL - stop using relative include
> paths in pdfium?
Lei, I made a stab at this once but ran out of patience trying to get it
to work under all the possible build environments:
{platforms} x {standalone vs. chromium} x {gyp vs. gn} x {master vs. xfa}

[Lei Zhang, 2015-06-05 19:14:50]

On 2015/06/05 19:12:26, Tom Sepez wrote:
> On 2015/06/05 19:04:19, Lei Zhang wrote:
> > Have we considered the alternative to this CL - stop using relative include
> > paths in pdfium?
> Lei, I made a stab at this once but ran out of patience trying to get it
> to work under all the possible build environments:
> {platforms} x {standalone vs. chromium} x {gyp vs. gn} x {master vs. xfa}

OK, I fugured. We'll probably have a better chance after we merge the XFA
branch.

[brettw, 2015-06-05 19:59:33]

lgtm

[Tom Sepez, 2015-06-05 20:01:51]

The CQ bit was checked by tsepez@chromium.org

[commit-bot: I haz the power, 2015-06-05 20:04:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-05 20:04:12]

Commit queue rejected this change because it did not recognize the base URL.
Please commit your change manually.

[Tom Sepez, 2015-06-05 20:06:55]

Committed patchset #4 (id:60001) manually as
46ce8cb60364e9e0b21a81136c7debdddfd063a8 (presubmit successful).