emulate java_library static_deps with Bazel exports

In Soong, java_library can specify static_deps which are dependencies
that get aggregated into the final jar (akin to static linking). This is
useful because it allows dependencies higher up in the chain to compile
against the APIs exported by transitive dependencies. Bazel does not
support this functionality directly, but it can be emulated via the
exports attribute which makes any targets listed in the attribute public
to targets further up the chain.

Bug: 217236083
Bug: 219908977
Test: b build //external/error_prone:error_prone_core
Test: b build //external/bouncycastle:bouncycastle-host
Test: b build --platforms=//build/bazel/platforms:linux_x86
  //prebuilts/sdk/tools/jetifier/jetifier-standalone:jetifier
Change-Id: I2867e3f816de720a6f4bd9ff7a847d1b0c2da2d6
diff --git a/java/app.go b/java/app.go
index 96fd61a..8728df6 100755
--- a/java/app.go
+++ b/java/app.go
@@ -1450,7 +1450,8 @@
 }
 
 type bazelAndroidAppAttributes struct {
-	*javaLibraryAttributes
+	*javaCommonAttributes
+	Deps             bazel.LabelListAttribute
 	Manifest         bazel.Label
 	Custom_package   *string
 	Resource_files   bazel.LabelListAttribute
@@ -1460,7 +1461,16 @@
 
 // ConvertWithBp2build is used to convert android_app to Bazel.
 func (a *AndroidApp) ConvertWithBp2build(ctx android.TopDownMutatorContext) {
-	libAttrs := a.convertLibraryAttrsBp2Build(ctx)
+	commonAttrs, depLabels := a.convertLibraryAttrsBp2Build(ctx)
+
+	deps := depLabels.Deps
+	if !commonAttrs.Srcs.IsEmpty() {
+		deps.Append(depLabels.StaticDeps) // we should only append these if there are sources to use them
+	} else if !deps.IsEmpty() || !depLabels.StaticDeps.IsEmpty() {
+		ctx.ModuleErrorf("android_app has dynamic or static dependencies but no sources." +
+			" Bazel does not allow direct dependencies without sources nor exported" +
+			" dependencies on android_binary rule.")
+	}
 
 	manifest := proptools.StringDefault(a.aaptProperties.Manifest, "AndroidManifest.xml")
 
@@ -1483,7 +1493,8 @@
 	}
 
 	attrs := &bazelAndroidAppAttributes{
-		libAttrs,
+		commonAttrs,
+		deps,
 		android.BazelLabelForModuleSrcSingle(ctx, manifest),
 		// TODO(b/209576404): handle package name override by product variable PRODUCT_MANIFEST_PACKAGE_NAME_OVERRIDES
 		a.overridableAppProperties.Package_name,