Remove old BUILD file merging code

It's not needed anymore since aosp/2197837,
it should've been removed in that cl but I forgot.

Bug: 234167862
Test: ./build/bazel/ci/bp2build.sh
Change-Id: I3d67a6e1894ad401525070ad37d3158708898306

android/allowlists/allowlists.go

@@ -295,6 +295,7 @@ var (
 		"external/bazel-skylib":/* recursive = */ true,
 		"external/guava":/* recursive = */ true,
 		"external/jsr305":/* recursive = */ true,
+		"external/protobuf":/* recursive = */ false,
 		"frameworks/ex/common":/* recursive = */ true,
 
 		"packages/apps/Music":/* recursive = */ true,
@@ -302,6 +303,7 @@ var (
 
 		"prebuilts/bazel":/* recursive = */ true,
 		"prebuilts/bundletool":/* recursive = */ true,
+		"prebuilts/clang/host/linux-x86":/* recursive = */ false,
 		"prebuilts/gcc":/* recursive = */ true,
 		"prebuilts/build-tools":/* recursive = */ true,
 		"prebuilts/jdk/jdk11":/* recursive = */ false,

android/bazel.go

@@ -17,9 +17,6 @@ package android
 import (
 	"bufio"
 	"errors"
-	"fmt"
-	"io/ioutil"
-	"path/filepath"
 	"strings"
 
 	"github.com/google/blueprint"
@@ -117,7 +114,6 @@ type Bazelable interface {
 	GetBazelLabel(ctx BazelConversionPathContext, module blueprint.Module) string
 	ShouldConvertWithBp2build(ctx BazelConversionContext) bool
 	shouldConvertWithBp2build(ctx bazelOtherModuleContext, module blueprint.Module) bool
-	GetBazelBuildFileContents(c Config, path, name string) (string, error)
 	ConvertWithBp2build(ctx TopDownMutatorContext)
 
 	// namespacedVariableProps is a map from a soong config variable namespace
@@ -498,28 +494,6 @@ func bp2buildDefaultTrueRecursively(packagePath string, config allowlists.Bp2Bui
 	return false, packagePath
 }
 
-// GetBazelBuildFileContents returns the file contents of a hand-crafted BUILD file if available or
-// an error if there are errors reading the file.
-// TODO(b/181575318): currently we append the whole BUILD file, let's change that to do
-// something more targeted based on the rule type and target.
-func (b *BazelModuleBase) GetBazelBuildFileContents(c Config, path, name string) (string, error) {
-	if !strings.Contains(b.HandcraftedLabel(), path) {
-		return "", fmt.Errorf("%q not found in bazel_module.label %q", path, b.HandcraftedLabel())
-	}
-	name = filepath.Join(path, name)
-	f, err := c.fs.Open(name)
-	if err != nil {
-		return "", err
-	}
-	defer f.Close()
-
-	data, err := ioutil.ReadAll(f)
-	if err != nil {
-		return "", err
-	}
-	return string(data[:]), nil
-}
-
 func registerBp2buildConversionMutator(ctx RegisterMutatorsContext) {
 	ctx.TopDown("bp2build_conversion", convertWithBp2build).Parallel()
 }