Revert of Mandoline: Add WebGL support

Revert of Mandoline: Add WebGL support (patchset #9 id:180001 of https://codereview.chromium.org/1338433002/ )

Reason for revert:
Unfortunately, this broke `gn check` with an improper dependency.

http://build.chromium.org/p/chromium.linux/builders/Linux%20GN/builds/32063/steps/gn_check/logs/stdio

I have a patch in-flight that will re-enable gn check on the trybots so that this breakages don't get through, but in the meantime I'm reverting this.

Sorry!

Original issue's description:
> This change adds WebGL support in mandoline. It also adds GL
> chromium_framebuffer_multisample extension which is need by
> WebGL.
>
> TODO:
>   * Pass attributes to GPU when create WebGL context.
>   * Get GPU info and fill it into glinfo.
>
> TEST= mandoline --enable-webgl http://learningwebgl.com/lessons/lesson03/index.html
> BUG=525159
> NOPRESUBMIT=true
>
> Committed: https://crrev.com/ab7a90daddbe7d44558d8703b12204570ae98431
> Cr-Commit-Position: refs/heads/master@{#349206}

TBR=sky@chromium.org,piman@chromium.org,fsamuel@chromium.org,penghuang@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=525159
Committed: https://crrev.com/c6374e2ea63356bd00853ae2dde9b4bcdb204a92
Cr-Commit-Position: refs/heads/master@{#349226}

[Dirk Pranke, 2015-09-16 20:54:05]

Created Revert of Mandoline: Add WebGL support

[commit-bot: I haz the power, 2015-09-16 20:54:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1343303003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1343303003/1

[commit-bot: I haz the power, 2015-09-16 20:56:42]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-16 20:57:27]

Patchset 1 (id:??) landed as
https://crrev.com/c6374e2ea63356bd00853ae2dde9b4bcdb204a92
Cr-Commit-Position: refs/heads/master@{#349226}