Revert "Flag to control if generated SDK prebuilts are preferred."

This reverts commit d0b99cea0a.

Reason for revert: Not needed anymore. We will simple exclude the 
gernated Android.bp files from prebuilt drops instead, it keeps
things simpler.

Change-Id: I5b01b2e01197f9fceb4630c8ade95f0d1d0f33f4

sdk/sdk.go

@@ -93,10 +93,6 @@ type sdkProperties struct {
 	//   dropped. Adding a rule to members that have //visibility:private will
 	//   cause the //visibility:private to be discarded.
 	Prebuilt_visibility []string
-
-	// Specifying whether the generated prebuilt SDK build rule should have the
-	// prefer flag set or not.
-	Prebuilts_prefer *bool // default: false
 }
 
 // Contains information about the sdk properties that list sdk members, e.g.
@@ -296,10 +292,6 @@ func (s *sdk) snapshot() bool {
 	return s.properties.Snapshot
 }
 
-func (s *sdk) PreferPrebuilts() bool {
-	return proptools.BoolDefault(s.properties.Prebuilts_prefer, false)
-}
-
 func (s *sdk) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	if s.snapshot() {
 		// We don't need to create a snapshot out of sdk_snapshot.

sdk/sdk_test.go

@@ -662,68 +662,3 @@ sdk_snapshot {
 		)
 	})
 }
-
-// Ensure that sdk prebuilt_prefer works correctly.
-func TestSnapshot_PrebuiltPreferTrue(t *testing.T) {
-	bp := `
-		sdk {
-			name: "mysdk",
-			java_header_libs: ["myjavalib"],
-			prebuilts_prefer: true,
-		}
-
-		java_library {
-			name: "myjavalib",
-			srcs: ["Test.java"],
-			system_modules: "none",
-			sdk_version: "none",
-			compile_dex: true,
-			host_supported: true,
-		}
-	`
-	preparer := android.GroupFixturePreparers(
-		prepareForSdkTestWithJava,
-		android.FixtureWithRootAndroidBp(bp),
-	)
-
-	checkZipFile := func(t *testing.T, result *android.TestResult, expected string) {
-		zipRule := result.ModuleForTests("mysdk", "common_os").Rule("SnapshotZipFiles")
-		android.AssertStringEquals(t, "snapshot zip file", expected, zipRule.Output.String())
-	}
-
-	t.Run("prefer=true", func(t *testing.T) {
-		result := android.GroupFixturePreparers(
-			preparer,
-		).RunTest(t)
-
-		checkZipFile(t, result, "out/soong/.intermediates/mysdk/common_os/mysdk-current.zip")
-
-		CheckSnapshot(t, result, "mysdk", "",
-			checkAndroidBpContents(`
-// This is auto-generated. DO NOT EDIT.
-
-java_import {
-    name: "mysdk_myjavalib@current",
-    sdk_member_name: "myjavalib",
-    visibility: ["//visibility:public"],
-    apex_available: ["//apex_available:platform"],
-    jars: ["java/myjavalib.jar"],
-}
-
-java_import {
-    name: "myjavalib",
-    prefer: true,
-    visibility: ["//visibility:public"],
-    apex_available: ["//apex_available:platform"],
-    jars: ["java/myjavalib.jar"],
-}
-
-sdk_snapshot {
-    name: "mysdk@current",
-    visibility: ["//visibility:public"],
-    java_header_libs: ["mysdk_myjavalib@current"],
-}
-			`),
-		)
-	})
-}

sdk/update.go

@@ -32,9 +32,8 @@ import (
 // ========================================================
 //
 // SOONG_SDK_SNAPSHOT_PREFER
-//     By default every unversioned module in the generated snapshot has prefer set by the
+//     By default every unversioned module in the generated snapshot has prefer: false. Building it
-//     sdk.prebuilts_prefer property. Building it with SOONG_SDK_SNAPSHOT_PREFER=true will force
+//     with SOONG_SDK_SNAPSHOT_PREFER=true will force them to use prefer: true.
-//     them to use prefer: true.
 //
 // SOONG_SDK_SNAPSHOT_VERSION
 //     This provides control over the version of the generated snapshot.
@@ -1624,11 +1623,11 @@ func (s *sdk) createMemberSnapshot(ctx *memberContext, member *sdkMember, bpModu
 
 	// Do not add the prefer property if the member snapshot module is a source module type.
 	if !memberType.UsesSourceModuleTypeInSnapshot() {
-		// Set the prefer based on the environment variable if present, else the sdk.prefer_prebuilts
+		// Set the prefer based on the environment variable. This is a temporary work around to allow a
-		// value.
+		// snapshot to be created that sets prefer: true.
 		// TODO(b/174997203): Remove once the ability to select the modules to prefer can be done
 		//  dynamically at build time not at snapshot generation time.
-		prefer := ctx.sdkMemberContext.Config().IsEnvTrue("SOONG_SDK_SNAPSHOT_PREFER") || s.PreferPrebuilts()
+		prefer := ctx.sdkMemberContext.Config().IsEnvTrue("SOONG_SDK_SNAPSHOT_PREFER")
 
 		// Set prefer. Setting this to false is not strictly required as that is the default but it does
 		// provide a convenient hook to post-process the generated Android.bp file, e.g. in tests to