Track printer installations for each configuration.

chromeos/printing/printer_configuration.h

Index: chromeos/printing/printer_configuration.h
diff --git a/chromeos/printing/printer_configuration.h b/chromeos/printing/printer_configuration.h
index 27f047bdb93e39bca6b49c6b55131a04df2dc48a..1b55339d70772d475489e5780140005d3896bc4a 100644
--- a/chromeos/printing/printer_configuration.h
+++ b/chromeos/printing/printer_configuration.h
@@ -47,7 +47,7 @@ class CHROMEOS_EXPORT Printer {
   Printer();
 
   // Constructs a printer object with an id.
-  explicit Printer(const std::string& id);
+  explicit Printer(const std::string& id, int64_t last_updated = 0);
 
   // Copy constructor and assignment.
   Printer(const Printer& printer);
@@ -93,6 +93,10 @@ class CHROMEOS_EXPORT Printer {
   Source source() const { return source_; }
   void set_source(const Source source) { source_ = source; }
 
+  // Returns the timestamp for the most recent update.  Returns 0 if the
+  // printer was not created with a valid timestamp.
+  int64_t last_updated() const { return last_updated_; }
+
  private:
   // Globally unique identifier. Empty indicates a new printer.
   std::string id_;
@@ -121,6 +125,9 @@ class CHROMEOS_EXPORT Printer {
 
   // The datastore which holds this printer.
   Source source_;
+
+  // Timestamp of most recent change.
+  int64_t last_updated_;
 };
 
 }  // namespace chromeos