Fix some problems detected by coverity.

- Uninitialized class member in GSCanonicalEntry and SkPDFDocument.
- Incorrect sign extension in SkPDFFont.
- Dead code in SkPDFUtils.

CID=16262,16272,16273,16275

Review URL: http://codereview.appspot.com/4659041

git-svn-id: http://skia.googlecode.com/svn/trunk@1668 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed