Move ExtensionSystem into extensions namespace

chrome/browser/extensions/extension_system_factory.h

Index: chrome/browser/extensions/extension_system_factory.h
diff --git a/chrome/browser/extensions/extension_system_factory.h b/chrome/browser/extensions/extension_system_factory.h
index a6c0c9eb51f40571fd7321ffea18c2049432e0e2..80411f3b80a52c144595427a594e6fa07967c3a3 100644
--- a/chrome/browser/extensions/extension_system_factory.h
+++ b/chrome/browser/extensions/extension_system_factory.h
@@ -10,15 +10,19 @@
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
-class ExtensionSystem;
 class Profile;
 class ProfileKeyedService;
 
+namespace extensions {
+class ExtensionSystem;
+}
+
 // ProfileKeyedServiceFactory for ExtensionSystemImpl::Shared.
 // Should not be used except by ExtensionSystem(Factory).
 class ExtensionSystemSharedFactory : public ProfileKeyedServiceFactory {
  public:
-  static ExtensionSystemImpl::Shared* GetForProfile(Profile* profile);
+  static extensions::ExtensionSystemImpl::Shared* GetForProfile(
+      Profile* profile);
 
   static ExtensionSystemSharedFactory* GetInstance();
 
@@ -37,7 +41,7 @@ class ExtensionSystemSharedFactory : public ProfileKeyedServiceFactory {
 class ExtensionSystemFactory : public ProfileKeyedServiceFactory {
  public:
   // ProfileKeyedServiceFactory implementation:
-  static ExtensionSystem* GetForProfile(Profile* profile);
+  static extensions::ExtensionSystem* GetForProfile(Profile* profile);
 
   static ExtensionSystemFactory* GetInstance();