Reduce FOR_EACH_OBSERVER usage in extensions

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 <memory>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 49 matching lines @@
 
 void PrinterProviderInternalAPI::RemoveObserver(
     PrinterProviderInternalAPIObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void PrinterProviderInternalAPI::NotifyGetPrintersResult(
     const Extension* extension,
     int request_id,
     const PrinterProviderInternalAPIObserver::PrinterInfoVector& printers) {
-  FOR_EACH_OBSERVER(PrinterProviderInternalAPIObserver, observers_,
-                    OnGetPrintersResult(extension, request_id, printers));
+  for (auto& observer : observers_)
+    observer.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));
+  for (auto& observer : observers_)
+    observer.OnGetCapabilityResult(extension, request_id, capability);
 }
 
 void PrinterProviderInternalAPI::NotifyPrintResult(
     const Extension* extension,
     int request_id,
     api::printer_provider_internal::PrintError error) {
-  FOR_EACH_OBSERVER(PrinterProviderInternalAPIObserver, observers_,
-                    OnPrintResult(extension, request_id, error));
+  for (auto& observer : observers_)
+    observer.OnPrintResult(extension, request_id, error);
 }
 
 void PrinterProviderInternalAPI::NotifyGetUsbPrinterInfoResult(
     const Extension* extension,
     int request_id,
     const api::printer_provider::PrinterInfo* printer_info) {
-  FOR_EACH_OBSERVER(
-      PrinterProviderInternalAPIObserver, observers_,
-      OnGetUsbPrinterInfoResult(extension, request_id, printer_info));
+  for (auto& observer : observers_)
+    observer.OnGetUsbPrinterInfoResult(extension, request_id, printer_info);
 }
 
 PrinterProviderInternalReportPrintResultFunction::
     PrinterProviderInternalReportPrintResultFunction() {
 }
 
 PrinterProviderInternalReportPrintResultFunction::
     ~PrinterProviderInternalReportPrintResultFunction() {
 }
 
@@ skipping 152 matching lines @@
   EXTENSION_FUNCTION_VALIDATE(params.get());
 
   PrinterProviderInternalAPI::GetFactoryInstance()
       ->Get(browser_context())
       ->NotifyGetUsbPrinterInfoResult(extension(), params->request_id,
                                       params->printer_info.get());
   return RespondNow(NoArguments());
 }
 
 }  // namespace extensions