Add the transitive dependencies of boot_image to apex

This avoids having to specify boot libraries in both the boot_image
and separately as java_libs on the apex. Simply add them to the
boot_image (happens automatically ATM when using image_name: "art")
and add the boot_image to the apex.

Bug: 177892522
Test: m nothing
Change-Id: I7e0c41665604b73780cdf0dc555067497b1e6ef0

java/boot_image.go

@@ -70,6 +70,10 @@ var bootImageContentDepTag = bootImageContentDependencyTag{}
 
 var _ android.ExcludeFromVisibilityEnforcementTag = bootImageContentDepTag
 
+func IsbootImageContentDepTag(tag blueprint.DependencyTag) bool {
+	return tag == bootImageContentDepTag
+}
+
 type bootImageProperties struct {
 	// The name of the image this represents.
 	//
@@ -182,8 +186,8 @@ func (i BootImageInfo) AndroidBootImageFilesByArchType() map[android.ArchType]an
 func (b *BootImageModule) DepIsInSameApex(ctx android.BaseModuleContext, dep android.Module) bool {
 	tag := ctx.OtherModuleDependencyTag(dep)
 	if tag == bootImageContentDepTag {
-		// Boot image contents are not automatically added to apex, yet.
-		return false
+		// Boot image contents are automatically added to apex.
+		return true
 	}
 	if android.IsMetaDependencyTag(tag) {
 		// Cross-cutting metadata dependencies are metadata.