Enable the Sky compositor

Enable the Sky compositor

Turns out we need to reset the context before switching back to drawing with
Ganesh (i.e., call resetContext on the GrContext) to clean out whatever state we've
changed in the GL context. Now the city-list and the flights-app demos work.

R=esprehn@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/bd0d09a82756b8dcb60234b7db22011229edc70c

[abarth-chromium, 2014-11-21 17:48:07]

abarth@chromium.org changed reviewers:
+ eseidel@chromium.org, ojan@chromium.org, rafaelw@chromium.org

[esprehn, 2014-11-21 17:53:18]

esprehn@chromium.org changed reviewers:
+ esprehn@chromium.org

[esprehn, 2014-11-21 17:53:19]

lgtm

https://codereview.chromium.org/752653002/diff/1/sky/compositor/layer_host.cc
File sky/compositor/layer_host.cc (right):

https://codereview.chromium.org/752653002/diff/1/sky/compositor/layer_host.cc...
sky/compositor/layer_host.cc:55: ganesh_context_.gr()->resetContext();
Why not do this inside the Display() call like before?

[abarth-chromium, 2014-11-21 17:53:52]

abarth@chromium.org changed reviewers:
- esprehn@chromium.org

[abarth-chromium, 2014-11-21 17:56:51]

abarth@chromium.org changed reviewers:
+ esprehn@chromium.org

[abarth-chromium, 2014-11-21 17:56:52]

https://codereview.chromium.org/752653002/diff/1/sky/compositor/layer_host.cc
File sky/compositor/layer_host.cc (right):

https://codereview.chromium.org/752653002/diff/1/sky/compositor/layer_host.cc...
sky/compositor/layer_host.cc:55: ganesh_context_.gr()->resetContext();
On 2014/11/21 at 17:53:19, esprehn wrote:
> Why not do this inside the Display() call like before?

It doesn't really matter today because we only have one Layer.  I've tried to
set things up so that we can have more than one layer (e.g., between each child
mojo::View).  Conceptually, we should only enter Ganesh mode once and then draw
all the layers, which is why I moved this here.

[abarth-chromium, 2014-11-21 17:57:55]

Committed patchset #1 (id:1) manually as
bd0d09a82756b8dcb60234b7db22011229edc70c (presubmit successful).

[esprehn, 2014-11-21 17:58:34]

On 2014/11/21 at 17:56:52, abarth wrote:
> https://codereview.chromium.org/752653002/diff/1/sky/compositor/layer_host.cc
> File sky/compositor/layer_host.cc (right):
> 
>
https://codereview.chromium.org/752653002/diff/1/sky/compositor/layer_host.cc...
> sky/compositor/layer_host.cc:55: ganesh_context_.gr()->resetContext();
> On 2014/11/21 at 17:53:19, esprehn wrote:
> > Why not do this inside the Display() call like before?
> 
> It doesn't really matter today because we only have one Layer.  I've tried to
set things up so that we can have more than one layer (e.g., between each child
mojo::View).  Conceptually, we should only enter Ganesh mode once and then draw
all the layers, which is why I moved this here.

Okay. Child mojo::View's are cross process though right? I think we should
always have a flat list of layers interspersed with layers from another
mojo::View that are painted by someone else?

[abarth-chromium, 2014-11-21 17:59:27]

On 2014/11/21 at 17:58:34, esprehn wrote:
> Okay. Child mojo::View's are cross process though right?

Yes.

> I think we should always have a flat list of layers interspersed with layers
from another mojo::View that are painted by someone else?

Yeah.  The idea is that won't have a tree of layers.  We'll just have a list of
layers.