java_sdk_library: Remove requirement for api_packages to be specified

If api_packages is not set then will try and generate stubs from all
the source packages.

Bug: 145998881
Test: m checkbuild
Change-Id: Ic9d7f82bb34c4b960a2f17614d7f64ddd13ad8b0
diff --git a/java/sdk_library.go b/java/sdk_library.go
index d69339b..3fc1803 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -97,7 +97,10 @@
 	// List of Java libraries that will be in the classpath when building stubs
 	Stub_only_libs []string `android:"arch_variant"`
 
-	// list of package names that will be documented and publicized as API
+	// list of package names that will be documented and publicized as API.
+	// This allows the API to be restricted to a subset of the source files provided.
+	// If this is unspecified then all the source files will be treated as being part
+	// of the API.
 	Api_packages []string
 
 	// list of package names that must be hidden from the API
@@ -707,11 +710,6 @@
 		return
 	}
 
-	if len(module.sdkLibraryProperties.Api_packages) == 0 {
-		mctx.PropertyErrorf("api_packages", "java_sdk_library must specify api_packages")
-		return
-	}
-
 	// If this builds against standard libraries (i.e. is not part of the core libraries)
 	// then assume it provides both system and test apis. Otherwise, assume it does not and
 	// also assume it does not contribute to the dist build.