GLRasterizationContext is now responsible for doing GPU rasterization.
It can coexist with its target NativeSurface, so we don't have to
continually recreate NativeSurfaces when doing GPU rasterization.
process parts.
This will make it easier to adapt to IPC.
The trickiest part here was to make script tasks spawn new layout tasks
directly instead of having the pipeline do it for them. The latter
approach will not work in multiprocess mode, because layout and script
must run in the same address space and the pipeline cannot inject tasks
into another process.
an IPC channel instead.
Because this used a boxed trait object to invoke messages across a
process boundary, and boxed trait objects are not supported across IPC,
we spawn a helper thread inside the compositor to perform the marshaling
for us.
Now that NativeDisplay can be shared between the compositor and the
paint task, we can move the LayerBuffer cache to the compositor. This
allows surfaces to be potentially reused between different paint tasks
and will eventually allow OpenGL contexts to be preserved between
instances of GL rasterization.
Update to latest rust-layers
The compositing context, painting context and display metadata have all
been collapsed into a single NativeDisplay class.
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Getting these down to the embedding API level required that I redo the bindings generator again, so this is more commits than anticipated.
@mbrubeck @Manishearth @pcwalton but NOT @larsbergstrom so don't even look at this.
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This fixes various race conditions that affect test execution when using the servodriver product. It doesn't yet do enough to make servodriver a viable alternative to the normal servo test executor.
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* Wait for the correct pipeline to return a LoadComplete message
before signalling a load is complete, and ensure that the root
pipeline is the one corresponding to the active document of the top
level browsing context, even if this has not yet painted.
* Ensure that TakeScreenshot operates on the correct pipeline
* Reset the screenshot ready flag whenever we decide that we are ready
to take a screenshot.
This is important for the SERVO_HEADLESS configuration, because
creating a clipboard on linux creates an X context which then causes
reftest instability.
Example output from the memory profiler:
```
| 1.04 MiB -- url(http://en.wikipedia.org/wiki/Main_Page)
| 0.26 MiB -- display-list
| 0.78 MiB -- paint-task # new output line
| 0.78 MiB -- buffer-map # new output line
```
The buffer maps aren't huge, but they're worth measuring, and it's good
to get the memory profiler plumbing into PaintTask.
I've done a bit of job to get this done. Right now readback is still used, but we have a `LayerId` -> `CanvasRenderer` map on the paint task, that we can use to get rid of that.
I'd want review, to see if this is a good approach (I know it's not the initial `CanvasId` -> renderer approach, but it's pretty similar, since a canvas involves a `PaintLayer`).
I had to do a bit of refactoring to avoid cyclic dependencies between canvas and gfx. I'd want you to review them too.
It's mergeable and doesn't break any tests :P
Some of my main concerns:
* Does the canvas render really need to be behind an `Arc<Mutex<T>>`?
* I can't clone a `NativeSurface` right now (that's why the `SendNativeSurface()` msg is unimplemented in the WebGL task). It should be easy to add that to rust-layers, supposing the caller is responsible to mark it as non-leaking, any reason to not do it?
cc @jdm @pcwalton
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