Make OutputPath implement objPathProvider

Needed to allow OutputPath to replace some usages of ModuleOutPath.

Bug: 179124768
Test: m droid
Change-Id: I0f746a11c53ed8c9c9193b57afc0b06c0249ff75

android/paths.go

@@ -1011,8 +1011,13 @@ func (p OutputPath) buildDir() string {
 	return p.config.buildDir
 }
 
+func (p OutputPath) objPathWithExt(ctx ModuleOutPathContext, subdir, ext string) ModuleObjPath {
+	return PathForModuleObj(ctx, subdir, pathtools.ReplaceExtension(p.path, ext))
+}
+
 var _ Path = OutputPath{}
 var _ WritablePath = OutputPath{}
+var _ objPathProvider = OutputPath{}
 
 // toolDepPath is a Path representing a dependency of the build tool.
 type toolDepPath struct {