Fixed more fuzzer issues

- Added the "isAvailable" function to check how much bytes are remaining in the stream before doing potentially large mallocs. That way, we can signal a bad stream instead of crashing.
- Added data validation in SkImageInfo.cpp
- Added NULL pointer check in displacement
- Modified the fuzzer for randomized bitmap types

BUG=328934,329254
R=senorblanco@google.com, senorblanco@chromium.org, reed@google.com, sugoi@google.com

Author: sugoi@chromium.org

Review URL: https://codereview.chromium.org/116773002

git-svn-id: http://skia.googlecode.com/svn/trunk@12723 2bbb7eff-a529-9590-31e7-b0007b416f81
13 files changed