In NativeAOT builds, _AddResourceDesignerToPublishFiles ran after
_ComputeManagedAssemblyToLink, so the designer assembly was not in
ManagedAssemblyToLink. ILLink skipped the designer assembly entirely
and did not rewrite its netstandard references.

Fix by adding _AddResourceDesignerToPublishFiles to _PrepareLinking's
DependsOnTargets, so the designer is passed to ILLink.

# Conflicts:
#	src/Microsoft.Android.Sdk.ILLink/Microsoft.Android.Sdk.ILLink.csproj

FixAbstractMethodsStep was moved from ILLink to the post-trim pipeline
on main (7ae24aa). The merge conflict resolution incorrectly kept the
Compile include, but the file now uses types not available in the ILLink
project (IAssemblyModifierPipelineStep, StepContext, Properties.Resources).

…rties

FixLegacyResourceDesignerStep now runs in PostTrimmingPipeline (after ILLink)
instead of as an ILLink custom step. Previously, the step ran before MarkStep
and rewrote library assemblies to reference designer properties, which caused
MarkStep to preserve them. Now that the rewriting happens after ILLink, we
must root the designer assembly so all resource properties survive trimming.

Add TrimmerRootAssembly for the designer in _AddResourceDesignerToPublishFiles.
This keeps IsTrimmable=true (action=link) so ILLink still rewrites the
netstandard assembly reference, but roots all types so nothing is trimmed.

An alternative approach would be to run FixLegacyResourceDesignerStep before
ILLink instead of after. That would allow ILLink to trim unused resource
properties from the designer (since the rewritten references would already be
in place for MarkStep), but it would also process resource references in
assemblies that ILLink may later remove entirely.

… assembly

TrimmerRootAssembly (-a flag) makes the designer an entry point, which
causes ILLink to retain netstandard.dll as a dependency, leaking it into
the APK (+19KB). TrimmerRootDescriptor (-x flag) preserves all designer
types/members without making it an entry point, avoiding the regression.

…builds

FixLegacyResourceDesignerStep now runs in PostTrimmingPipeline (MSBuild
task) instead of inside ILLink, so the error code is always XA8000
regardless of build configuration.

WriteLinesToFile was regenerating the TrimmerRootDescriptor XML on every
build, changing its timestamp and causing ILLink to re-run on incremental
builds. Adding WriteOnlyWhenDifferent preserves the timestamp when the
content hasn't changed.

…is fixed

Run FixLegacyResourceDesignerStep *before* ILLink instead of after it,
so the trimmer sees the rewritten IL (call instructions to designer
property getters) and can freely trim unused designer types. This
removes the need to root the entire designer assembly via a
TrimmerRootDescriptor during trimming, eliminating the APK size
regression.

…efficiency

Both _PreTrimmingFixLegacyDesigner and _PostTrimmingPipeline were including
all .dll files from ResolvedFileToPublish, which includes satellite resource
assemblies (.resources.dll) from the shared NuGet package cache. These tasks
open assemblies with ReadWrite access via DirectoryAssemblyResolver, causing
IOException when parallel multi-RID builds contend for locks on the same
cached files.

Filter both targets to only process items where PostprocessAssembly metadata
is 'true', which excludes satellite assemblies that ILLink does not process.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The resolver was using ReadWrite=true, which acquires exclusive file locks on
every assembly it loads — including the shared _Microsoft.Android.Resource.Designer.dll
that is loaded implicitly via Resolve() during FixLegacyResourceDesignerStep.LoadDesigner().

The designer DLL is built once in the outer build at a shared obj/ path, but
this task runs in each inner per-RID build. Parallel RID builds contend for
exclusive locks on the shared file, causing IOException.

Since the task only reads the designer assembly (never writes it), drop
ReadWrite=true so all assemblies are opened in shared read mode. Library
assemblies that get modified are written back using an explicit output path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>