Add boot_images to apex

Previously, the apex module had to hard code behavior specific to the
art apex module in order to include the art boot image. This change
adds support to the apex module to allow the boot images to be
specified per apex.

In combination with a change to add the "art-boot-image" to the ART
apex this allows the custom code for handling the art boot image in
apex to be removed.

That custom apex code also included the logic to ensure that the
GlobalSoongConfig was initialized for use by the dex_bootjars
singleton. That logic has been moved from the APEX to the boot_image
module. That ensures that it will be run if and only if a boot_image
module is present in the checked out repos. So, limited manifest
checkouts which do not contain the art or frameworks/base repos (which
is where the boot_image modules are defined) will not attempt to run
this logic, which would fail because dex2oat would not be present.

Bug: 177892522
Test: m droid
Change-Id: I02d25fbef6e864e31eb5e0f4eb50358c79486db0

java/boot_image.go

@@ -15,9 +15,11 @@
 package java
 
 import (
+	"fmt"
 	"strings"
 
 	"android/soong/android"
+	"android/soong/dexpreopt"
 	"github.com/google/blueprint"
 )
 
@@ -38,6 +40,7 @@ type bootImageProperties struct {
 
 type BootImageModule struct {
 	android.ModuleBase
+	android.ApexModuleBase
 
 	properties bootImageProperties
 }
@@ -46,6 +49,7 @@ func bootImageFactory() android.Module {
 	m := &BootImageModule{}
 	m.AddProperties(&m.properties)
 	android.InitAndroidArchModule(m, android.HostAndDeviceDefault, android.MultilibCommon)
+	android.InitApexModule(m)
 	return m
 }
 
@@ -53,6 +57,9 @@ var BootImageInfoProvider = blueprint.NewProvider(BootImageInfo{})
 
 type BootImageInfo struct {
 	// The image config, internal to this module (and the dex_bootjars singleton).
+	//
+	// Will be nil if the BootImageInfo has not been provided for a specific module. That can occur
+	// when SkipDexpreoptBootJars(ctx) returns true.
 	imageConfig *bootImageConfig
 }
 
@@ -60,12 +67,56 @@ func (i BootImageInfo) Modules() android.ConfiguredJarList {
 	return i.imageConfig.modules
 }
 
+// Get a map from ArchType to the associated boot image's contents for Android.
+//
+// Extension boot images only return their own files, not the files of the boot images they extend.
+func (i BootImageInfo) AndroidBootImageFilesByArchType() map[android.ArchType]android.OutputPaths {
+	files := map[android.ArchType]android.OutputPaths{}
+	if i.imageConfig != nil {
+		for _, variant := range i.imageConfig.variants {
+			// We also generate boot images for host (for testing), but we don't need those in the apex.
+			// TODO(b/177892522) - consider changing this to check Os.OsClass = android.Device
+			if variant.target.Os == android.Android {
+				files[variant.target.Arch.ArchType] = variant.imagesDeps
+			}
+		}
+	}
+	return files
+}
+
+func (b *BootImageModule) DepIsInSameApex(ctx android.BaseModuleContext, dep android.Module) bool {
+	tag := ctx.OtherModuleDependencyTag(dep)
+	if tag == dexpreopt.Dex2oatDepTag {
+		// The dex2oat tool is only needed for building and is not required in the apex.
+		return false
+	}
+	panic(fmt.Errorf("boot_image module %q should not have a dependency on %q via tag %s", b, dep, android.PrettyPrintTag(tag)))
+}
+
+func (b *BootImageModule) ShouldSupportSdkVersion(ctx android.BaseModuleContext, sdkVersion android.ApiLevel) error {
+	return nil
+}
+
+func (b *BootImageModule) DepsMutator(ctx android.BottomUpMutatorContext) {
+	if SkipDexpreoptBootJars(ctx) {
+		return
+	}
+
+	// Add a dependency onto the dex2oat tool which is needed for creating the boot image. The
+	// path is retrieved from the dependency by GetGlobalSoongConfig(ctx).
+	dexpreopt.RegisterToolDeps(ctx)
+}
+
 func (b *BootImageModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	// Nothing to do if skipping the dexpreopt of boot image jars.
 	if SkipDexpreoptBootJars(ctx) {
 		return
 	}
 
+	// Force the GlobalSoongConfig to be created and cached for use by the dex_bootjars
+	// GenerateSingletonBuildActions method as it cannot create it for itself.
+	dexpreopt.GetGlobalSoongConfig(ctx)
+
 	// Get a map of the image configs that are supported.
 	imageConfigs := genBootImageConfigs(ctx)