Add PrepareForTestWithBuildFlag

Add a helper function that creates a test fixture preparer that
sets a build flag, and use it everywhere that was setting build flags
manually.

Test: all soong tests
Flag: EXEMPT refactor
Change-Id: I68d50d68787a30d091f0827e8caa51f5c5a762ef
diff --git a/java/sdk_library_test.go b/java/sdk_library_test.go
index 911e8b1..368eca7 100644
--- a/java/sdk_library_test.go
+++ b/java/sdk_library_test.go
@@ -35,11 +35,7 @@
 			"29": {"foo"},
 			"30": {"bar", "barney", "baz", "betty", "foo", "fred", "quuz", "wilma"},
 		}),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		droiddoc_exported_dir {
 			name: "droiddoc-templates-sdk",
@@ -537,11 +533,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -934,11 +926,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -987,11 +975,7 @@
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
 		preparer,
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib",
@@ -1183,11 +1167,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib.source_preferred_using_legacy_flags", "sdklib.prebuilt_preferred_using_legacy_flags"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	).RunTestWithBp(t, bp)
 
 	// Make sure that rdeps get the correct source vs prebuilt based on mainline_module_contributions
@@ -1369,11 +1349,7 @@
 			"sdklib_group_foo",
 			"sdklib_owner_foo",
 			"foo"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_HIDDEN_API_EXPORTABLE_STUBS": "true",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_HIDDEN_API_EXPORTABLE_STUBS", "true"),
 	).RunTestWithBp(t, `
 		java_sdk_library {
 			name: "sdklib_no_group",
@@ -1785,12 +1761,8 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				// We can use any of the apex contribution build flags from build/soong/android/config.go#mainlineApexContributionBuildFlags here
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		// We can use any of the apex contribution build flags from build/soong/android/config.go#mainlineApexContributionBuildFlags here
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	)
 
 	result := fixture.RunTestWithBp(t, bp)
@@ -1873,11 +1845,7 @@
 		prepareForJavaTest,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("sdklib", "sdklib.v1", "sdklib.v2"),
-		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
-			variables.BuildFlags = map[string]string{
-				"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "my_mainline_module_contributions",
-			}
-		}),
+		android.PrepareForTestWithBuildFlag("RELEASE_APEX_CONTRIBUTIONS_ADSERVICES", "my_mainline_module_contributions"),
 	)
 
 	for _, tc := range testCases {