Clean up bookmark related codes.

Remove CPDF_Dictionary*() operator in CPDF_Bookmark class.
Unify naming conventions and coding styles.
Change some functions to const.

Change the name of function argument to |pDict| for FPDF_xxx type variable.
This makes the code more clear and gives better variable naming

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/828203002
3 files changed