Implement bp2build for the package module

* We are interested mostly in the conversion the `default_applicable_licenses`
  attribute, as `default_visibility` cannot be handled until every module's
  `visibility` is handled.
* Several referenced license modules had to be manually enabled for
  conversion, and likewise a few trivial Android.bp containing only
  package and license modules.
* As Bazel allows only a single `package` rule, the package rules in a
  manually converted BUILD.bazel files were removed (in
  external/protobuf and prebuilts/clang/host/linux-x86 trees).
* The converted package rule is emitted before the `load` statements per
  Bazel documentation.

Bug: 190817312
Test: treehugger
Change-Id: If8bf6fee1580177de3bb402923615bcd48923ed2

android/package.go

@@ -15,6 +15,7 @@
 package android
 
 import (
+	"android/soong/bazel"
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
 )
@@ -37,12 +38,33 @@ type packageProperties struct {
 	Default_applicable_licenses []string
 }
 
+type bazelPackageAttributes struct {
+	Default_visibility          []string
+	Default_applicable_licenses bazel.LabelListAttribute
+}
+
 type packageModule struct {
 	ModuleBase
+	BazelModuleBase
 
 	properties packageProperties
 }
 
+var _ Bazelable = &packageModule{}
+
+func (p *packageModule) ConvertWithBp2build(ctx TopDownMutatorContext) {
+	ctx.CreateBazelTargetModule(
+		bazel.BazelTargetModuleProperties{
+			Rule_class: "package",
+		},
+		CommonAttributes{},
+		&bazelPackageAttributes{
+			Default_applicable_licenses: bazel.MakeLabelListAttribute(BazelLabelForModuleDeps(ctx, p.properties.Default_applicable_licenses)),
+			// FIXME(asmundak): once b/221436821 is resolved
+			Default_visibility: []string{"//visibility:public"},
+		})
+}
+
 func (p *packageModule) GenerateAndroidBuildActions(ModuleContext) {
 	// Nothing to do.
 }
@@ -59,7 +81,7 @@ func (p *packageModule) qualifiedModuleId(ctx BaseModuleContext) qualifiedModule
 func PackageFactory() Module {
 	module := &packageModule{}
 
-	module.AddProperties(&module.properties)
+	module.AddProperties(&module.properties, &module.commonProperties.BazelConversionStatus)
 
 	// The name is the relative path from build root to the directory containing this
 	// module. Set that name at the earliest possible moment that information is available
@@ -76,5 +98,7 @@ func PackageFactory() Module {
 	// its checking and parsing phases so make it the primary licenses property.
 	setPrimaryLicensesProperty(module, "default_applicable_licenses", &module.properties.Default_applicable_licenses)
 
+	InitBazelModule(module)
+
 	return module
 }