Move ExtensionHost into extensions namespace

chrome/browser/content_settings/content_settings_platform_app_provider.cc

Index: chrome/browser/content_settings/content_settings_platform_app_provider.cc
diff --git a/chrome/browser/content_settings/content_settings_platform_app_provider.cc b/chrome/browser/content_settings/content_settings_platform_app_provider.cc
index fef6da23ade50d5bdefa3faebe43e9c3cfded807..18a2e88c8039d3748a758140d90938325bc091e9 100644
--- a/chrome/browser/content_settings/content_settings_platform_app_provider.cc
+++ b/chrome/browser/content_settings/content_settings_platform_app_provider.cc
@@ -67,8 +67,8 @@ void PlatformAppProvider::Observe(int type,
                                   const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_EXTENSION_HOST_CREATED: {
-      const ExtensionHost* host =
-          content::Details<ExtensionHost>(details).ptr();
+      const extensions::ExtensionHost* host =
+          content::Details<extensions::ExtensionHost>(details).ptr();
       if (host->extension()->is_platform_app())
         SetContentSettingForExtension(host->extension(), CONTENT_SETTING_BLOCK);
       break;