Fix the code that causes warnings

Fix the code that causes warnings

These are the left or newly added code which causes compilation
warnings of "signed and unsigned comparison". Need to fix them
before I re-enable the warning flag.

BUG=pdfium:29
Committed: https://pdfium.googlesource.com/pdfium/+/3cc01f2ba255f4b7584668ee2b8e5ed97792c26d

[Wei Li, 2016-05-16 19:44:37]

weili@chromium.org changed reviewers:
+ dsinclair@chromium.org, thestig@chromium.org

[Wei Li, 2016-05-16 19:44:38]

pls review, thanks

[dsinclair, 2016-05-16 19:49:30]

The CQ bit was checked by dsinclair@chromium.org

[dsinclair, 2016-05-16 19:49:31]

lgtm

[commit-bot: I haz the power, 2016-05-16 19:49:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1986533002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1986533002/1

[commit-bot: I haz the power, 2016-05-16 20:53:45]

Description was changed from

==========
Fix the code that causes warnings

These are the left or newly added code which causes compilation
warnings of "signed and unsigned comparison". Need to fix them
before I re-enable the warning flag.

BUG=pdfium:29
==========

to

==========
Fix the code that causes warnings

These are the left or newly added code which causes compilation
warnings of "signed and unsigned comparison". Need to fix them
before I re-enable the warning flag.

BUG=pdfium:29

Committed:
https://pdfium.googlesource.com/pdfium/+/3cc01f2ba255f4b7584668ee2b8e5ed97792...
==========

[commit-bot: I haz the power, 2016-05-16 20:53:47]

Committed patchset #1 (id:1) as
https://pdfium.googlesource.com/pdfium/+/3cc01f2ba255f4b7584668ee2b8e5ed97792...