Add onGetUsbPrinterInfoRequested event to printerProvider API.

extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h

Index: extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h
diff --git a/extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h b/extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h
index 611e3118ef8b9aada128d5adbc5a43f40e46feed..9e1da1ad422c088fa89f87b2536bb98f5cf8641a 100644
--- a/extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h
+++ b/extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h
@@ -48,6 +48,7 @@ class PrinterProviderInternalAPI : public BrowserContextKeyedAPI {
   friend class PrinterProviderInternalReportPrintersFunction;
   friend class PrinterProviderInternalReportPrinterCapabilityFunction;
   friend class PrinterProviderInternalReportPrintResultFunction;
+  friend class PrinterProviderInternalReportUsbPrinterInfoFunction;
 
   // BrowserContextKeyedAPI implementation.
   static const bool kServiceRedirectedInIncognito = true;
@@ -75,6 +76,14 @@ class PrinterProviderInternalAPI : public BrowserContextKeyedAPI {
                          int request_id,
                          core_api::printer_provider_internal::PrintError error);
 
+  // Notifies observers that a printerProvider.onGetUsbPrinterInfoRequested
+  // callback has been called. Called from
+  // |PrinterProviderInternalReportUsbPrinterInfoFunction|.
+  void NotifyGetUsbPrinterInfoResult(
+      const Extension* extension,
+      int request_id,
+      const core_api::printer_provider::PrinterInfo* printer_info);
+
   ObserverList<PrinterProviderInternalAPIObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(PrinterProviderInternalAPI);
@@ -151,6 +160,22 @@ class PrinterProviderInternalGetPrintDataFunction
   DISALLOW_COPY_AND_ASSIGN(PrinterProviderInternalGetPrintDataFunction);
 };
 
+class PrinterProviderInternalReportUsbPrinterInfoFunction
+    : public UIThreadExtensionFunction {
+ public:
+  PrinterProviderInternalReportUsbPrinterInfoFunction();
+
+ protected:
+  ~PrinterProviderInternalReportUsbPrinterInfoFunction() override;
+  ExtensionFunction::ResponseAction Run() override;
+
+ private:
+  DECLARE_EXTENSION_FUNCTION("printerProviderInternal.reportUsbPrinterInfo",
+                             PRINTERPROVIDERINTERNAL_REPORTUSBPRINTERINFO)
+
+  DISALLOW_COPY_AND_ASSIGN(PrinterProviderInternalReportUsbPrinterInfoFunction);
+};
+
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_INTERNAL_PRINTER_PROVIDER_INTERNAL_API_H_