Plug IOSurface leak at context tear-down.

Plug IOSurface leak at context tear-down.

Change the ordering of the destruction of a command buffer's
surface and context, so that the context is current while the
surface is destroyed.

Add lots of asserts to the surface tear-down path to verify
that we have the context that we need in order to delete the
resources.

If we don't delete the FBO and texture, then they will hold a
reference to the IOSurface until the share group is destroyed,
which, in the case of tabs opened from Gmail, may be a very
long time in the future.

BUG=158469
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=168151

[ccameron, 2012-11-15 23:36:43]

This plugs the last of the IOSurface leaks.  With this and the other patch
checked in, we always stay at or below 8 IOSurfaces (the 8 is the arbitrary
constant that was in the memory manager).

[Ken Russell (switch to Gerrit), 2012-11-16 02:33:23]

LGTM. Thank you for tracking this down. I think you should request that this be
merged back to earlier releases after it has baked in Canary for a while. I
think it will fix longstanding resource leaks in situations where new tabs are
created in response to clicking links in other tabs.

[commit-bot: I haz the power, 2012-11-16 03:04:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ccameron@chromium.org/11418015/4001

[commit-bot: I haz the power, 2012-11-16 07:36:07]

Change committed as 168151