aura: use TestWebGraphicsContext3D for the shared contexts

aura: use TestWebGraphicsContext3D for the shared contexts

Previously, we would use a regular command buffer context for the shared
offscreen contexts, which is unable to share resources with the
TestWebGraphicsContext3D, raising asserts if for example filters are used in
layers.
This change makes us use TestWebGraphicsContext3D for all contexts when using
--test-compositor

BUG=139300
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=149357

[sky, 2012-07-31 19:06:41]

Do you need to update gyp files too? I don't think we build
TestWebGraphicsContext3D outside of tests.

[piman, 2012-07-31 19:54:31]

On Tue, Jul 31, 2012 at 12:06 PM, <sky@chromium.org> wrote:

> Do you need to update gyp files too? I don't think we build
> TestWebGraphicsContext3D outside of tests.
>

We do build it (I checked).
FTR try jobs passed.


>
https://chromiumcodereview.**appspot.com/10828088/<https://chromiumcodereview...
>

[sky, 2012-07-31 23:35:29]

LGTM

[commit-bot: I haz the power, 2012-07-31 23:42:46]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/piman@chromium.org/10828088/1

[commit-bot: I haz the power, 2012-08-01 00:31:55]

Try job failure for 10828088-1 (retry) on win for step "compile" (clobber
build).
It's a second try, previously, step "compile" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win&number...

[commit-bot: I haz the power, 2012-08-01 01:12:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/piman@chromium.org/10828088/8002

[commit-bot: I haz the power, 2012-08-01 02:33:41]

Change committed as 149357