Mac: Fix compile error due to issue #2009 changes

libcef/browser/web_plugin_impl.cc

@@ -30,6 +30,9 @@ void PluginsCallbackImpl(
   }
 }
 
+#if !(defined(WIDEVINE_CDM_AVAILABLE) && defined(ENABLE_PEPPER_CDMS)) || \
+    defined(OS_LINUX)
+
 void DeliverWidevineCdmError(const std::string& error_message,
                              CefRefPtr<CefRegisterCdmCallback> callback) {
   LOG(ERROR) << error_message;
@@ -41,6 +44,8 @@ void DeliverWidevineCdmError(const std::string& error_message,
   }
 }
 
+#endif
+
 }  // namespace