Adds a build flag for GL to never use vertex attributes that don't have per-vertex values.
Also promotes the ATTRIBUTE_MATRIX flag that was local to cpp files to the public config file.

Review URL: http://codereview.appspot.com/4434057/

git-svn-id: http://skia.googlecode.com/svn/trunk@1155 2bbb7eff-a529-9590-31e7-b0007b416f81
11 files changed