Mozart: Avoid blocking in glCheckFramebufferStatus().

Mozart: Avoid blocking in glCheckFramebufferStatus().

glCheckFramebufferStatus() causes the GL command buffer to be
flushed which can block for a very long time and significantly
hurts performance.

Changed the Ganesh image factory to only ask for an ordinary texture
rather than a rendering target when binding to a mailbox.  Skia
checks the framebuffer status eagerly when creating a rendering
target which causes a stall.  This code path gets hit every time
the compositor accepts an image from an app (so usually at least
once per frame per app).

Changed the GL renderer to avoid checking framebuffer status
except on the first frame in debug mode (as a sanity check).

BUG=
R=mikejurka@google.com

Committed: https://chromium.googlesource.com/external/mojo/+/d75adea16bd51dcc1aac1d2f416544454b4d84ba

[jeffbrown, 2016-05-20 00:21:31]

jeffbrown@google.com changed reviewers:
+ abarth@google.com, mikejurka@google.com

[mikejurka, 2016-05-20 00:31:25]

lgtm

awesome!!

[jeffbrown, 2016-05-20 20:18:46]

Description was changed from

==========
Mozart: Avoid blocking in glCheckFramebufferStatus().

glCheckFramebufferStatus() causes the GL command buffer to be
flushed which can block for a very long time and significantly
hurts performance.

Changed the Ganesh image factory to only ask for an ordinary texture
rather than a rendering target when binding to a mailbox.  Skia
checks the framebuffer status eagerly when creating a rendering
target which causes a stall.  This code path gets hit every time
the compositor accepts an image from an app (so usually at least
once per frame per app).

Changed the GL renderer to avoid checking framebuffer status
except on the first frame in debug mode (as a sanity check).

BUG=
==========

to

==========
Mozart: Avoid blocking in glCheckFramebufferStatus().

glCheckFramebufferStatus() causes the GL command buffer to be
flushed which can block for a very long time and significantly
hurts performance.

Changed the Ganesh image factory to only ask for an ordinary texture
rather than a rendering target when binding to a mailbox.  Skia
checks the framebuffer status eagerly when creating a rendering
target which causes a stall.  This code path gets hit every time
the compositor accepts an image from an app (so usually at least
once per frame per app).

Changed the GL renderer to avoid checking framebuffer status
except on the first frame in debug mode (as a sanity check).

BUG=
R=mikejurka@google.com

Committed:
https://chromium.googlesource.com/external/mojo/+/d75adea16bd51dcc1aac1d2f416...
==========

[jeffbrown, 2016-05-20 20:18:47]

Committed patchset #1 (id:1) manually as
d75adea16bd51dcc1aac1d2f416544454b4d84ba (presubmit successful).