This reverts commit ebb5b909fbb10dad2275acd4fc8ec1d9744a0bf6.
Seeing the following breakage on host build:
```
../../flutter/flow/scene_update_context.cc:205:36: error: non-const lvalue reference to type 'flutter::MutatorsStack' cannot bind to a value of unrelated type 'const flutter::Stopwatch'
frame.context().raster_time(),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../flutter/flow/scene_update_context.cc:207:36: error: no viable conversion from 'flutter::TextureRegistry' to 'const flutter::Stopwatch'
frame.context().texture_registry(),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../flutter/flow/instrumentation.h:55:32: note: candidate constructor not viable: no known conversion from 'flutter::TextureRegistry' to 'const flutter::Stopwatch &' for 1st argument
FML_DISALLOW_COPY_AND_ASSIGN(Stopwatch);
^
../../flutter/fml/macros.h:28:3: note: expanded from macro 'FML_DISALLOW_COPY_AND_ASSIGN'
TypeName(const TypeName&) = delete; \
^
../../flutter/flow/scene_update_context.cc:208:36: error: non-const lvalue reference to type 'flutter::TextureRegistry' cannot bind to a temporary of type 'flutter::RasterCache *'
&frame.context().raster_cache(),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../flutter/flow/scene_update_context.cc:209:36: error: cannot initialize a member subobject of type 'const flutter::RasterCache *' with an rvalue of type 'bool'
false};
^~~~~
```
For https://github.com/flutter/flutter/issues/33807
We still need to make layers' children immutable for full immutability.
That will require us to change the SceneBuilder API to build the layer
bottom up instead of top down (post-order traversal instead of pre-order
traversal).
When we visit a PlatformViewLayer during the paint traversal it replaces
the PaintContext's canvas with a new one that is painted ontop of the
embedded view.
We need to make sure that operations applied by parent layers are also
applied to the new canvas.
To achieve this we collect all the canvases in a SkNWayCanvas and use
this canvas by non leaf nodes. Leaf nodes still paint only to the "current"
canvas.
This PR moves the overlay canvas creation from the paint phase to the
preroll phase, collects them into a SkNWayCanvas and set it in
PaintContext.
To keep this PR focused, I only used the internal_nodes_canvas in the
tranform_layer.
Will followup with a PR that changes all internal layers to use the
internal_nodes_canvas.
The overlay surfaces are going to be the same IOSSurface implementation
with the platform views controller set to null (so these are surfaces
that don't support embedding platform views to them).
* Adds a FlutterOverlayView which is a UIView that's showing an
overlay surface.
* Creates an overlay surface for each embedded UIView (done in
FlutterPlatformViewsController).
* Changes CompositeEmbeddedView to return a new canvas.
* Makes the PlatformViewLayer replace the PaintContext's canvas with
the canvas for the overlay view.
* Changed canvas in PaintContext to be a pointer so it can be changed.
TBD in following PRs:
* Copy the current canvas state when replacing a canvas in PaintContext.
* Make FlutterOverlayView work with a GL backend (currently it only
works with software rendering)
For flow to manipulate the embedded UIViews during the paint traversal
it needs some hook in PaintContext.
This PR introduces a ViewEmbeder interface that is implemented by the
iOS PlatformViewsController and plumbs it into PaintContext.
The ViewEmbedder interface is mainly a place holder at this point, as
this PR is focused on just the plumbing.
