Switch bp2build mutator to bottom up

This should be no-op, as the underlying mutator has not changed yet.

Some other refactoring is required and done in this CL:

- Delete some old, dead ApiBp2build code
- Fix casting to TopDownMutator when it's not necessary

This change is required to prepare for allowlist v2 work, as only
BottomUp mutators can AddDependency.

Bug: 285631638
Test: m nothing
Test: presubmits
Change-Id: I5212a5f5634cc13056195783e6df37ff8eb000da

cc/library_headers.go

@@ -15,8 +15,6 @@
 package cc
 
 import (
-	"github.com/google/blueprint/proptools"
-
 	"android/soong/android"
 	"android/soong/bazel"
 	"android/soong/bazel/cquery"
@@ -175,106 +173,6 @@ func apiBazelTargets(ll bazel.LabelList) bazel.LabelList {
 	return bazel.MakeLabelList(labels)
 }
 
-func apiLibraryHeadersBp2Build(ctx android.TopDownMutatorContext, module *Module) {
-	// cc_api_library_headers have a 1:1 mapping to arch/no-arch
-	// For API export, create a top-level arch-agnostic target and list the arch-specific targets as its deps
-
-	// arch-agnostic includes
-	apiIncludes := getModuleLibApiIncludes(ctx, module)
-	// arch and os specific includes
-	archApiIncludes, androidOsIncludes := archOsSpecificApiIncludes(ctx, module)
-	for _, arch := range allArches { // sorted iteration
-		archApiInclude := archApiIncludes[arch]
-		if !archApiInclude.isEmpty() {
-			createApiHeaderTarget(ctx, archApiInclude)
-			apiIncludes.addDep(archApiInclude.name)
-		}
-	}
-	// os==android includes
-	if !androidOsIncludes.isEmpty() {
-		createApiHeaderTarget(ctx, androidOsIncludes)
-		apiIncludes.addDep(androidOsIncludes.name)
-	}
-
-	if !apiIncludes.isEmpty() {
-		// override the name from <mod>.module-libapi.headers --> <mod>.contribution
-		apiIncludes.name = android.ApiContributionTargetName(module.Name())
-		createApiHeaderTarget(ctx, apiIncludes)
-	}
-}
-
-func createApiHeaderTarget(ctx android.TopDownMutatorContext, includes apiIncludes) {
-	props := bazel.BazelTargetModuleProperties{
-		Rule_class:        "cc_api_library_headers",
-		Bzl_load_location: "//build/bazel/rules/apis:cc_api_contribution.bzl",
-	}
-	ctx.CreateBazelTargetModule(
-		props,
-		android.CommonAttributes{
-			Name:     includes.name,
-			SkipData: proptools.BoolPtr(true),
-		},
-		&includes.attrs,
-	)
-}
-
 var (
 	allArches = []string{"arm", "arm64", "x86", "x86_64"}
 )
-
-type archApiIncludes map[string]apiIncludes
-
-func archOsSpecificApiIncludes(ctx android.TopDownMutatorContext, module *Module) (archApiIncludes, apiIncludes) {
-	baseProps := bp2BuildParseBaseProps(ctx, module)
-	i := bp2BuildParseExportedIncludes(ctx, module, &baseProps.includes)
-	archRet := archApiIncludes{}
-	for _, arch := range allArches {
-		includes := i.Includes.SelectValue(
-			bazel.ArchConfigurationAxis,
-			arch)
-		systemIncludes := i.SystemIncludes.SelectValue(
-			bazel.ArchConfigurationAxis,
-			arch)
-		deps := baseProps.deps.SelectValue(
-			bazel.ArchConfigurationAxis,
-			arch)
-		attrs := bazelCcLibraryHeadersAttributes{
-			Export_includes:        bazel.MakeStringListAttribute(includes),
-			Export_system_includes: bazel.MakeStringListAttribute(systemIncludes),
-		}
-		apiDeps := apiBazelTargets(deps)
-		if !apiDeps.IsEmpty() {
-			attrs.Deps = bazel.MakeLabelListAttribute(apiDeps)
-		}
-		apiIncludes := apiIncludes{
-			name: android.ApiContributionTargetName(module.Name()) + "." + arch,
-			attrs: bazelCcApiLibraryHeadersAttributes{
-				bazelCcLibraryHeadersAttributes: attrs,
-				Arch:                            proptools.StringPtr(arch),
-			},
-		}
-		archRet[arch] = apiIncludes
-	}
-
-	// apiIncludes for os == Android
-	androidOsDeps := baseProps.deps.SelectValue(bazel.OsConfigurationAxis, bazel.OsAndroid)
-	androidOsAttrs := bazelCcLibraryHeadersAttributes{
-		Export_includes: bazel.MakeStringListAttribute(
-			i.Includes.SelectValue(bazel.OsConfigurationAxis, bazel.OsAndroid),
-		),
-		Export_system_includes: bazel.MakeStringListAttribute(
-			i.SystemIncludes.SelectValue(bazel.OsConfigurationAxis, bazel.OsAndroid),
-		),
-	}
-	androidOsApiDeps := apiBazelTargets(androidOsDeps)
-	if !androidOsApiDeps.IsEmpty() {
-		androidOsAttrs.Deps = bazel.MakeLabelListAttribute(androidOsApiDeps)
-	}
-	osRet := apiIncludes{
-		name: android.ApiContributionTargetName(module.Name()) + ".androidos",
-		attrs: bazelCcApiLibraryHeadersAttributes{
-			bazelCcLibraryHeadersAttributes: androidOsAttrs,
-		},
-	}
-	return archRet, osRet
-}