Revert of Fix WebGL 2 texture renderability check.

Revert of Fix WebGL 2 texture renderability check. (patchset #8 id:140001 of https://codereview.chromium.org/1412883002/ )

Reason for revert:
Failing on several configs, possibly has a bug:

On Windows, triggers a bug in ANGLE, should have a skip suppression:
http://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28NVIDIA%29/builds/11345
(assert in Renderer11.cpp in Debug)

On Mac, fails for unknown reasons:
http://build.chromium.org/p/chromium.gpu.fyi/builders/Mac%2010.10%20Release%20%28ATI%29/builds/5643
http://build.chromium.org/p/chromium.gpu.fyi/builders/Mac%2010.9%20Debug%20%28Intel%29/builds/21206

On Linux AMD, fails as well:
http://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/42849

Original issue's description:
> Fix WebGL 2 texture renderability check.
>
> It should check from base_level and up, not 0 and up.
>
> BUG=429053
> TEST=conformance2/textures/misc/tex-mipmap-levels.html, gpu_unittests
> R=bajones@chromium.org,kbr@chromium.org
>
> Committed: https://crrev.com/493f20d34a57ae22da78f798235881ff39465ae0
> Cr-Commit-Position: refs/heads/master@{#356475}

TBR=bajones@chromium.org,kbr@chromium.org,sievers@chromium.org,piman@chromium.org,qiankun.miao@intel.com,zmo@google.com,zmo@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=429053
Committed: https://crrev.com/96713d46c7291a773362015d1344b140c7711631
Cr-Commit-Position: refs/heads/master@{#356550}

[Jamie Madill, 2015-10-28 14:26:23]

Created Revert of Fix WebGL 2 texture renderability check.

[commit-bot: I haz the power, 2015-10-28 14:26:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1425943002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1425943002/1

[commit-bot: I haz the power, 2015-10-28 14:27:22]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-28 14:28:27]

Patchset 1 (id:??) landed as
https://crrev.com/96713d46c7291a773362015d1344b140c7711631
Cr-Commit-Position: refs/heads/master@{#356550}