Move enable extensions define to a build flag.

chrome/browser/profiles/profile_manager.cc

Index: chrome/browser/profiles/profile_manager.cc
diff --git a/chrome/browser/profiles/profile_manager.cc b/chrome/browser/profiles/profile_manager.cc
index bda2efea170bb7a6f94a7eab5baff390048e1be7..3a69b5e042999d0a461ac0d6f890292d44b5057f 100644
--- a/chrome/browser/profiles/profile_manager.cc
+++ b/chrome/browser/profiles/profile_manager.cc
@@ -87,13 +87,14 @@
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/common/content_switches.h"
+#include "extensions/features/features.h"
 #include "net/http/http_transaction_factory.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "net/url_request/url_request_job.h"
 #include "ui/base/l10n/l10n_util.h"
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "chrome/browser/extensions/extension_service.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
@@ -265,7 +266,7 @@ void CheckCryptohomeIsMounted(chromeos::DBusMethodCallStatus call_status,
 
 #endif
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 
 // Returns the number of installed (and enabled) apps, excluding any component
 // apps.
@@ -1126,7 +1127,7 @@ void ProfileManager::DoFinalInitForServices(Profile* profile,
                                             bool go_off_the_record) {
   TRACE_EVENT0("browser", "ProfileManager::DoFinalInitForServices");
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   // Ensure that the HostContentSettingsMap has been created before the
   // ExtensionSystem is initialized otherwise the ExtensionSystem will be
   // registered twice
@@ -1209,7 +1210,7 @@ void ProfileManager::DoFinalInitLogging(Profile* profile) {
   TRACE_EVENT0("browser", "ProfileManager::DoFinalInitLogging");
   // Count number of extensions in this profile.
   int enabled_app_count = -1;
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   enabled_app_count = GetEnabledAppCount(profile);
 #endif