Convert GN visibility variables to lists.

Currently this is either a list or a string. However, this is causing some problems because templates can't add to the invoker's visibility list without knowing if the original is a string or a list.

In an effort to make this consistent, I'm converting all visibiltiy to be lists, and will remove support for strings in a future build.

This exempts cld from header checking since it was confusing GN's header checker. It adds a ppapi header target as well that will be used by libyuv (that requires a roll).

TBR=scottmg

Review URL: https://codereview.chromium.org/544423002

Cr-Original-Commit-Position: refs/heads/master@{#293638}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9af4262ad8020658ee04c07d13a2617af64147b1
1 file changed