Skia is removing the deprecated legacy display setting globals and
associated kLegacyFontHost_InitType. This change replaces all such uses
with default surface properties with no special flags and an unknown
pixel geometry. Flutter never set the associated globals, leaving them
with their initial default values, which were no special flags and
horizontal RGB pixel geometry. The values used here are different but
this change should make no difference as Flutter never mentions
SkFont::kSubpixelAntiAlias to take advantage of the pixel geometry.

Cleans up header order/grouping for consistency: associated header, C/C++ system/standard library headers, library headers, platform-specific #includes.

Adds <cstring> where strlen, memcpy are being used: there are a bunch of places we use them transitively.

Applies linter-required cleanups. Disables linter on one file due to included RapidJson header. See https://github.com/flutter/flutter/issues/65676

This patch does not cover flutter/shell/platform/darwin. There's a separate, slightly more intensive cleanup for those in progress.

This reverts commit 4de62c7c.

This reverts commit d16ba48e.

This is part of a larger effort to expose the difference between GrDirectContext,
which runs on the GPU thread and can directly perform operations like uploading
textures, and GrRecordingContext, which can only queue up work to be delivered
to the GrDirectContext later.

Currently helps primarily on iOS when no BackdropFilter is present by lowering energy usage

* Revert "Add flow test fixtures and tests (#13986)"

This reverts commit 620f5281.

* Revert "Dynamically determine whether to use offscreen surface based on need (#13976)"

This reverts commit a86ef946.

Only use an offscreen surface on iOS if a layer which reads back from the destination surface, such as BackdropFilter, is present.

This reverts commit f456423c.

This is being reverted because it caused flutter/flutter#45098
(images don't load on iOS).

This reverts commit 2dcfaaeb.

This reverts commit 618e6666.

Revert "Always use `IOSGLContextSwitch` to access EAGLContexts to prevent plugins from polluting Flutter's EAGLContext (#13314)" (#13753)

Always use `IOSGLContextSwitch` to access EAGLContexts to prevent plugins from polluting Flutter's EAGLContext (#13314)

So it's the same with the GPU thread.

Otherwise, some shaders may be cached in binary on the IO thread, and we will lose them when we do the SkSL precompile.

For b/140174804

For https://github.com/flutter/flutter/issues/40686

Unit tests added:
- CacheSkSLWorks
- VisitFilesCanBeCalledTwice
- CanListFilesRecursively

This patch allows embedders to split the Flutter layer tree into multiple
chunks. These chunks are meant to be composed one on top of another. This gives
embedders a chance to interleave their own contents between these chunks.

The Flutter embedder API already provides hooks for the specification of
textures for the Flutter engine to compose within its own hierarchy (for camera
feeds, video, etc..). However, not all embedders can render the contents of such
sources into textures the Flutter engine can accept. Moreover, this composition
model may have overheads that are non-trivial for certain use cases. In such
cases, the embedder may choose to specify multiple render target for Flutter to
render into instead of just one.

The use of this API allows embedders to perform composition very similar to the
iOS embedder. This composition model is used on that platform for the embedding
of UIKit view such and web view and map views within the Flutter hierarchy.
However, do note that iOS also has threading configurations that are currently
not available to custom embedders.

The embedder API updates in this patch are ABI stable and existing embedders
will continue to work are normal. For embedders that want to enable this
composition mode, the API is designed to make it easy to opt into the same in an
incremental manner.

Rendering of contents into the “root” rendering surface remains unchanged.
However, now the application can push “platform views” via a scene builder.
These platform views need to handled by a FlutterCompositor specified in a new
field at the end of the FlutterProjectArgs struct.

When a new platform view in introduced within the layer tree, the compositor
will ask the embedder to create a new render target for that platform view.
Render targets can currently be OpenGL framebuffers, OpenGL textures or software
buffers. The type of the render target returned by the embedder must be
compatible with the root render surface. That is, if the root render surface is
an OpenGL framebuffer, the render target for each platform view must either be a
texture or a framebuffer in the same OpenGL context. New render target types as
well as root renderers for newer APIs like Metal & Vulkan can and will be added
in the future. The addition of these APIs will be done in an ABI & API stable
manner.

As Flutter renders frames, it gives the embedder a callback with information
about the position of the various platform views in the effective hierarchy.
The embedder is then meant to put the contents of the render targets that it
setup and had previously given to the engine onto the screen (of course
interleaving the contents of the platform views).

Unit-tests have been added that test not only the structure and properties of
layer hierarchy given to the compositor, but also the contents of the texels
rendered by a test compositor using both the OpenGL and software rendering
backends.

Fixes b/132812775
Fixes flutter/flutter#35410

This reverts commit 63c2c331.

* Revert "[fuchsia] Fix alignment of Fuchsia/non-Fuchsia tracing (#9289)"

This reverts commit f80ac5f5.

* Revert "Align fuchsia and non-fuchsia tracing (#9199)"

This reverts commit 78265484.

This is forward compatible with std::size and similar to how Chromium
removed use of the arraysize macro.

This follows our namespace change from shell to flutter: https://github.com/flutter/engine/pull/8520.

Fixes https://github.com/flutter/flutter/issues/28229

Behavior (visual) changes should be very minor. Things that are to be expected:
* A few things were not color managed correctly by the transform canvas (color emoji, some color filters). Those will be handled correctly with the tagged surfaces (although we're always transforming to sRGB, so nothing should change until we target a wider gamut).
* Image filtering will happen in the source color space, rather than the destination. Very minor.
* The transform canvas did caching of images in the destination color space. Now, the conversion happens at draw time. If there are performance issues, images can be pre-converted to the destination with makeColorSpace().

Ensure that the EGL rendering context is bound to the GPU thread in Rasterizer::MakeRasterSnapshot (#6816)

Fixes https://github.com/flutter/flutter/issues/24083

Moved the frame buffer specific logic from IOSGLContext to IOSGLRenderTarget.

use recording canvases for overlays

Support platform view overlays with gl rendering.

This also changes the overlay canvases (for both software and gl
rendering) be recording canvases, and only rasterize them after
finishing the paint traversal.