Add job id to JobEventDetails.

printing/printing_context_chromeos.h

Index: printing/printing_context_chromeos.h
diff --git a/printing/printing_context_chromeos.h b/printing/printing_context_chromeos.h
index efd2fb7cb1a30e0c21a8256c18704e54ff37dd21..eec0e38a23dc462da8f1b35ca9703f89f473a8ba 100644
--- a/printing/printing_context_chromeos.h
+++ b/printing/printing_context_chromeos.h
@@ -45,9 +45,6 @@ class PRINTING_EXPORT PrintingContextChromeos : public PrintingContext {
   // Lazily initializes |printer_|.
   Result InitializeDevice(const std::string& device);
 
-  // id for ongoing print job.  0 if no job is active.
-  int job_id_;
-
   CupsConnection connection_;
   std::unique_ptr<CupsPrinter> printer_;