Default metalava sandboxing to true

Turn on sandboxing everywhere.

Bug: 153703940
Test: m checkbuild
Change-Id: Ie64913d302efb780d5be9c1b32e6c368d72feba3

java/droidstubs.go

@@ -482,7 +482,7 @@ func (d *Droidstubs) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 
 	rule := android.NewRuleBuilder(pctx, ctx)
 
-	sandbox := proptools.Bool(d.Javadoc.properties.Sandbox)
+	sandbox := proptools.BoolDefault(d.Javadoc.properties.Sandbox, true)
 	if sandbox {
 		rule.Sbox(android.PathForModuleOut(ctx, "metalava"),
 			android.PathForModuleOut(ctx, "metalava.sbox.textproto")).

java/droidstubs_test.go

@@ -34,6 +34,7 @@ func TestDroidstubs(t *testing.T) {
 			srcs: ["bar-doc/a.java"],
 			api_levels_annotations_dirs: ["droiddoc-templates-sdk"],
 			api_levels_annotations_enabled: true,
+			sandbox: false,
 		}
 
 		droidstubs {
@@ -43,6 +44,7 @@ func TestDroidstubs(t *testing.T) {
 			api_levels_annotations_dirs: ["droiddoc-templates-sdk"],
 			api_levels_annotations_enabled: true,
 			api_levels_jar_filename: "android.other.jar",
+			sandbox: false,
 		}
 		`,
 		map[string][]byte{