Add check on Cube Completeness for Cube textures and improve the efficiency of checks associated with OES_texture_{half_}float_linear extension.

BUG=246815

Review URL: https://chromiumcodereview.appspot.com/16437002

git-svn-id: svn://svn.chromium.org/blink/trunk@152167 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed