java_sdk_library: Do not expose stubs implementation jar

The stubs header jar is optimized for use as a dependency for others
to use. It only changes if there is a significant difference in the
externals of the classes, i.e. anything that a library being compiled
against depends upon. So changes to implementations of method or the
addition/removal of private methods, fields will have no impact.

As there is no benefit in returning the implementation of the stubs
jar this change removes it. The implementation is still used when
taking a snapshot as the header jar is an internal build artefact
that is not suitable for long term snapshot.

Bug: 155164730
Test: m droid
Merged-In: If91b4d106683f23788547c537228c58be2867174
Change-Id: If91b4d106683f23788547c537228c58be2867174
(cherry picked from commit 23970f4285f2ba70b5a35a56a6dffa9afc1f37d9)
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 684a002..5efb4d0 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -694,7 +694,7 @@
 	return nil
 }
 
-func (c *commonToSdkLibraryAndImport) sdkJarsCommon(ctx android.BaseModuleContext, sdkVersion sdkSpec, headerJars bool) android.Paths {
+func (c *commonToSdkLibraryAndImport) selectHeaderJarsForSdkVersion(ctx android.BaseModuleContext, sdkVersion sdkSpec) android.Paths {
 
 	// If a specific numeric version has been requested then use prebuilt versions of the sdk.
 	if sdkVersion.version.isNumbered() {
@@ -725,11 +725,7 @@
 		return nil
 	}
 
-	if headerJars {
-		return paths.stubsHeaderPath
-	} else {
-		return paths.stubsImplPath
-	}
+	return paths.stubsHeaderPath
 }
 
 type SdkLibrary struct {
@@ -1200,7 +1196,7 @@
 		return module.HeaderJars()
 	}
 
-	return module.sdkJarsCommon(ctx, sdkVersion, headerJars)
+	return module.selectHeaderJarsForSdkVersion(ctx, sdkVersion)
 }
 
 // to satisfy SdkLibraryDependency interface
@@ -1639,11 +1635,7 @@
 }
 
 func (module *sdkLibraryImport) sdkJars(ctx android.BaseModuleContext, sdkVersion sdkSpec) android.Paths {
-
-	// The java_sdk_library_import can only ever give back header jars as it does not
-	// have an implementation jar.
-	headerJars := true
-	return module.sdkJarsCommon(ctx, sdkVersion, headerJars)
+	return module.selectHeaderJarsForSdkVersion(ctx, sdkVersion)
 }
 
 // to satisfy SdkLibraryDependency interface