Don't serialize extension user script injection results unless the extension

chrome/common/extensions/extension_messages.h

Index: chrome/common/extensions/extension_messages.h
diff --git a/chrome/common/extensions/extension_messages.h b/chrome/common/extensions/extension_messages.h
index c2fd98d711bc16bfb62320d3e8d6f2ce608c6468..8d3b3e19a9dc0d78c54b29ea17a5365f5b6f6571 100644
--- a/chrome/common/extensions/extension_messages.h
+++ b/chrome/common/extensions/extension_messages.h
@@ -117,6 +117,11 @@ IPC_STRUCT_BEGIN(ExtensionMsg_ExecuteCode_Params)
 
   // Whether the request is coming from a <webview>.
   IPC_STRUCT_MEMBER(bool, is_web_view)
+
+  // Whether the caller is interested in the result value. Manifest-declared
+  // content scripts and executeScript() calls without a response callback
+  // are examples of when this will be false.
+  IPC_STRUCT_MEMBER(bool, wants_result)
 IPC_STRUCT_END()
 
 // Struct containing the data for external connections to extensions. Used to