Simplify PDFiumEngine::CheckPageAvailable().

Simplify PDFiumEngine::CheckPageAvailable().

Also:
- Always check the return value from FPDFAvail_IsPageAvail().
- Change PDFiumPage::set_available(bool) to set_as_available().

[Lei Zhang, 2015-12-29 01:01:44]

Description was changed from

==========
Simplify PDFiumEngine::CheckPageAvailable().

Also always check the return value from FPDFAvail_IsPageAvail().
==========

to

==========
Simplify PDFiumEngine::CheckPageAvailable().

Also:
- Always check the return value from FPDFAvail_IsPageAvail().
- Change PDFiumPage::set_available(bool) to set_as_available().
==========

[Lei Zhang, 2015-12-29 01:04:28]

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

[spelchat, 2015-12-29 01:18:14]

lgtm

[Lei Zhang, 2015-12-29 03:41:42]

The CQ bit was checked by thestig@chromium.org

[commit-bot: I haz the power, 2015-12-29 03:42:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1550193002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1550193002/20001

[commit-bot: I haz the power, 2015-12-29 04:22:39]

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

[commit-bot: I haz the power, 2015-12-29 04:22:40]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)