Track printer installations for each configuration.

chrome/browser/chromeos/printing/printers_manager.h

Index: chrome/browser/chromeos/printing/printers_manager.h
diff --git a/chrome/browser/chromeos/printing/printers_manager.h b/chrome/browser/chromeos/printing/printers_manager.h
index f31bd6c7d0fd766ea22b6dbfa04392dd6a22b574..c8307c5b1ce934d15c2e6addaa008100926cd180 100644
--- a/chrome/browser/chromeos/printing/printers_manager.h
+++ b/chrome/browser/chromeos/printing/printers_manager.h
@@ -76,6 +76,12 @@ class PrintersManager : public KeyedService {
   // Returns a ModelTypeSyncBridge for the sync client.
   PrintersSyncBridge* GetSyncBridge();
 
+  // Registers that the printer was installed in CUPS.

[Lei Zhang, 2017/05/08 21:42:48]

One of the PrinterInstalled() callers is as follows:

manager->PrinterInstalled(*printer);
manager->RegisterPrinter(std::move(printer));

Can you better explain the difference between PrinterInstalled(), which
"registers the printer" in some way, vs RegisterPrinter()?

[skau, 2017/05/09 00:52:01]

I've tried to clarify the comment on RegisterPrinter to distinguish between the
two methods.  Let me know if you think it can be clearer.

[Lei Zhang, 2017/05/09 01:14:39]

Yes, definitely clearer.

+  void PrinterInstalled(const Printer& printer);
+
+  // Returns true if the printer is installed in CUPS.
+  bool IsConfigurationCurrent(const Printer& printer);

[Lei Zhang, 2017/05/08 21:42:48]

const method?

[skau, 2017/05/09 00:52:01]

Done.

+
  private:
   // Updates the in-memory recommended printer list.
   void UpdateRecommendedPrinters();
@@ -89,8 +95,10 @@ class PrintersManager : public KeyedService {
   // Contains the keys for all recommended printers in order so we can return
   // the list of recommended printers in the order they were received.
   std::vector<std::string> recommended_printer_ids_;
-  std::map<std::string, std::unique_ptr<base::DictionaryValue>>
-      recommended_printers_;
+  std::map<std::string, std::unique_ptr<Printer>> recommended_printers_;
+
+  // Map of printer ids to installation timestamps.
+  std::map<std::string, base::Time> installed_printer_timestamps_;
 
   base::ObserverList<Observer> observers_;