Fix infinite recursion in CPDF_Parser::ParseIndirectObjectAt().

Fix infinite recursion in CPDF_Parser::ParseIndirectObjectAt().

A suitably corrupted file can cause the parser(s) to repeatedly re-read
sections of the file at increasing parser recursion depth until the
stack is exhausted.  There is supposed to be a check for this based upon
the parser "level", but not all call paths pass or update the level as
required.

Much as I hate per-class statics, this introduces one to track the depth
so that the check is enforced no matter how screwy the call path might be
that leads the parser to re-enter itself. This is more palatable than trying
to find all these paths and fix them. We know this is OK since there is
only one thread in here modifying the static.

BUG=451830
R=thestig@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/a03932372b0906a340a6e3860c87e45f9ec79042

[Tom Sepez, 2015-01-26 23:16:59]

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

[Tom Sepez, 2015-01-26 23:17:09]

Lei, please review.

[Lei Zhang, 2015-01-27 00:43:32]

lgtm

Given the methods are public, it is harder to make sure all callers handle the
level correctly.

BTW, the commit message has a typo: s/matther/matter/

https://codereview.chromium.org/875263002/diff/1/core/include/fxcrt/fx_basic.h
File core/include/fxcrt/fx_basic.h (right):

https://codereview.chromium.org/875263002/diff/1/core/include/fxcrt/fx_basic....
core/include/fxcrt/fx_basic.h:1421: CFX_AutoRestorer(T* location) {
nit: explicit

[Tom Sepez, 2015-01-27 00:50:46]

https://codereview.chromium.org/875263002/diff/1/core/include/fxcrt/fx_basic.h
File core/include/fxcrt/fx_basic.h (right):

https://codereview.chromium.org/875263002/diff/1/core/include/fxcrt/fx_basic....
core/include/fxcrt/fx_basic.h:1421: CFX_AutoRestorer(T* location) {
On 2015/01/27 00:43:32, Lei Zhang wrote:
> nit: explicit

Done.

[Tom Sepez, 2015-01-27 00:51:26]

Committed patchset #2 (id:20001) manually as
a03932372b0906a340a6e3860c87e45f9ec79042 (presubmit successful).