Import new functionality for GL4 backend

Import functionality for new GL backend

Brings in the following functionality:

  ARB_draw_instanced
  ARB_instanced_arrays
  NV_bindless_texture
  EXT_direct_state_access
  KHR_debug

Also cleans up some of the NVPR extension loading.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/202c4c75fb806f751cf796850bf67fe9793e0643

Committed: https://skia.googlesource.com/skia/+/626e1ffe84c24a969dc56ca70ab2e950bf5034c4

[Chris Dalton, 2015-06-12 04:51:06]

cdalton@nvidia.com changed reviewers:
+ bsalomon@google.com

[bsalomon, 2015-06-12 16:11:00]

lgtm

[Chris Dalton, 2015-06-12 17:25:45]

The CQ bit was checked by cdalton@nvidia.com

[commit-bot: I haz the power, 2015-06-12 17:25:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1185573003/20001

[commit-bot: I haz the power, 2015-06-12 17:31:41]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/202c4c75fb806f751cf796850bf67fe9793e0643

[djsollen, 2015-06-12 19:00:50]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1184863002/ by djsollen@google.com.

The reason for reverting is: breaking multiple builds. For example...

https://uberchromegw.corp.google.com/i/client.skia/builders/Test-Ubuntu-GCC-G....

[Chris Dalton, 2015-06-12 20:17:45]

cdalton@nvidia.com changed reviewers:
+ caryclark@google.com

[Chris Dalton, 2015-06-12 20:42:12]

The CQ bit was checked by cdalton@nvidia.com to run a CQ dry run

[Chris Dalton, 2015-06-12 20:42:13]

The patchset sent to the CQ was uploaded after l-g-t-m from bsalomon@google.com
Link to the patchset: https://codereview.chromium.org/1185573003/#ps60001
(title: "fix KHR_debug suffixes")

[commit-bot: I haz the power, 2015-06-12 20:42:35]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1185573003/60001

[bsalomon, 2015-06-12 20:44:24]

lgtm

[bsalomon, 2015-06-12 20:44:24]

lgtm

lgtm

[commit-bot: I haz the power, 2015-06-12 20:53:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-12 20:53:45]

Dry run: This issue passed the CQ dry run.

[Chris Dalton, 2015-06-12 20:55:37]

The CQ bit was checked by cdalton@nvidia.com

[commit-bot: I haz the power, 2015-06-12 20:55:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1185573003/60001

[commit-bot: I haz the power, 2015-06-12 20:56:55]

Committed patchset #4 (id:60001) as
https://skia.googlesource.com/skia/+/626e1ffe84c24a969dc56ca70ab2e950bf5034c4