List printers managed by extensions in print preview

extensions/browser/api/printer_provider_internal/printer_provider_internal_api.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/api/printer_provider_internal/printer_provider_internal_api.h"
 
 #include "base/lazy_instance.h"
 #include "base/values.h"
 #include "extensions/common/api/printer_provider.h"
 #include "extensions/common/api/printer_provider_internal.h"
@@ skipping 29 matching lines @@
 }
 
 void PrinterProviderInternalAPI::RemoveObserver(
     PrinterProviderInternalAPIObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void PrinterProviderInternalAPI::NotifyGetPrintersResult(
     const Extension* extension,
     int request_id,
-    const base::ListValue& printers) {
+    const PrinterProviderInternalAPIObserver::PrinterInfoVector& printers) {
   FOR_EACH_OBSERVER(PrinterProviderInternalAPIObserver, observers_,
                     OnGetPrintersResult(extension, request_id, printers));
 }
 
 void PrinterProviderInternalAPI::NotifyGetCapabilityResult(
     const Extension* extension,
     int request_id,
     const base::DictionaryValue& capability) {
   FOR_EACH_OBSERVER(PrinterProviderInternalAPIObserver, observers_,
                     OnGetCapabilityResult(extension, request_id, capability));
@@ skipping 64 matching lines @@
 }
 
 ExtensionFunction::ResponseAction
 PrinterProviderInternalReportPrintersFunction::Run() {
   scoped_ptr<internal_api::ReportPrinters::Params> params(
       internal_api::ReportPrinters::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
 
   base::ListValue printers;
   if (params->printers) {
-    for (size_t i = 0; i < params->printers->size(); ++i) {
-      scoped_ptr<base::DictionaryValue> printer(
-          params->printers->at(i)->ToValue());
-      printer->SetString("extensionId", extension()->id());
-      printers.Append(printer.release());
-    }
+    PrinterProviderInternalAPI::GetFactoryInstance()
+        ->Get(browser_context())
+        ->NotifyGetPrintersResult(extension(), params->request_id,
+                                  *params->printers);
+  } else {
+    PrinterProviderInternalAPI::GetFactoryInstance()
+        ->Get(browser_context())
+        ->NotifyGetPrintersResult(
+            extension(), params->request_id,
+            PrinterProviderInternalAPIObserver::PrinterInfoVector());
   }
-
-  PrinterProviderInternalAPI::GetFactoryInstance()
-      ->Get(browser_context())
-      ->NotifyGetPrintersResult(extension(), params->request_id, printers);
   return RespondNow(NoArguments());
 }
 
 }  // namespace extensions