Support aapt2 resources flagging

This change modifies the aconfig and aapt2 build rules to support
resources flagging in aapt2.

Implementation details:
- Modify the aconfig text rule to include flag permission in the output
  text file
- Pass the `--flags-packages` argument to `aapt2 compile` command,
  similar to what is currently being done in the `aapt2 link` command

Bug: 344979955
Test: m nothing --no-skip-soong-tests
Change-Id: I3b0b1fd6dcd691b7cc50ba3d081ecafd82c2c904

java/aapt2.go

@@ -69,7 +69,7 @@ var aapt2CompileRule = pctx.AndroidStaticRule("aapt2Compile",
 
 // aapt2Compile compiles resources and puts the results in the requested directory.
 func aapt2Compile(ctx android.ModuleContext, dir android.Path, paths android.Paths,
-	flags []string, productToFilter string) android.WritablePaths {
+	flags []string, productToFilter string, featureFlagsPaths android.Paths) android.WritablePaths {
 	if productToFilter != "" && productToFilter != "default" {
 		// --filter-product leaves only product-specific resources. Product-specific resources only exist
 		// in value resources (values/*.xml), so filter value resource files only. Ignore other types of
@@ -85,6 +85,10 @@ func aapt2Compile(ctx android.ModuleContext, dir android.Path, paths android.Pat
 		flags = append([]string{"--filter-product " + productToFilter}, flags...)
 	}
 
+	for _, featureFlagsPath := range android.SortedUniquePaths(featureFlagsPaths) {
+		flags = append(flags, "--feature-flags", "@"+featureFlagsPath.String())
+	}
+
 	// Shard the input paths so that they can be processed in parallel. If we shard them into too
 	// small chunks, the additional cost of spinning up aapt2 outweighs the performance gain. The
 	// current shard size, 100, seems to be a good balance between the added cost and the gain.
@@ -112,6 +116,7 @@ func aapt2Compile(ctx android.ModuleContext, dir android.Path, paths android.Pat
 		ctx.Build(pctx, android.BuildParams{
 			Rule:        aapt2CompileRule,
 			Description: "aapt2 compile " + dir.String() + shardDesc,
+			Implicits:   featureFlagsPaths,
 			Inputs:      shard,
 			Outputs:     outPaths,
 			Args: map[string]string{