Add code needed to build skia as a windows dll within the chromium project.
- Export/import skia APIs if SKIA_DLL is defined.
- This change has no effect on skia.

Review URL: http://codereview.appspot.com/4282042

git-svn-id: http://skia.googlecode.com/svn/trunk@944 2bbb7eff-a529-9590-31e7-b0007b416f81
33 files changed