fix warnings on Mac in src/pdf

fix warnings on Mac in src/pdf

Fix these class of warnings:
- unused functions
- unused locals
- sign mismatch
- missing function prototypes
- missing newline at end of file
- 64 to 32 bit truncation

The changes prefer to link in dead code in the debug build
with 'if (false)' than to comment it out, but trivial cases
are commented out or sometimes deleted if it appears to be
a copy/paste error.
Committed: https://code.google.com/p/skia/source/detail?r=4178

[Steve VanDeBogart, 2012-06-17 02:10:37]

https://codereview.appspot.com/6299047/diff/2002/src/pdf/SkPDFCatalog.cpp
File src/pdf/SkPDFCatalog.cpp (right):

https://codereview.appspot.com/6299047/diff/2002/src/pdf/SkPDFCatalog.cpp#new...
src/pdf/SkPDFCatalog.cpp:41: size_t SkPDFCatalog::setFileOffset(SkPDFObject*
obj, size_t offset) {
Thanks for the cleanup.  Would it work to just change the argument type to off_t
instead of size_t here? fFileOffset appears to be an off_t anyway.  I think that
would remove a lot of the casts that you had to add.