Move enable extensions define to a build flag.

chrome/browser/download/chrome_download_manager_delegate.cc

Index: chrome/browser/download/chrome_download_manager_delegate.cc
diff --git a/chrome/browser/download/chrome_download_manager_delegate.cc b/chrome/browser/download/chrome_download_manager_delegate.cc
index 9af11e698d82f8eb1f78272b25964b9e0d5d3d83..bce81648e9dd7d2ff6e35be16cde7e780bacbfed 100644
--- a/chrome/browser/download/chrome_download_manager_delegate.cc
+++ b/chrome/browser/download/chrome_download_manager_delegate.cc
@@ -52,6 +52,7 @@
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/page_navigator.h"
+#include "extensions/features/features.h"
 #include "net/base/filename_util.h"
 #include "net/base/mime_util.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -66,7 +67,7 @@
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #endif
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "chrome/browser/extensions/api/downloads/downloads_api.h"
 #include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/webstore_installer.h"
@@ -288,7 +289,7 @@ bool ChromeDownloadManagerDelegate::ShouldOpenFileBasedOnExtension(
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (path.Extension().empty())
     return false;
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   // TODO(asanka): This determination is done based on |path|, while
   // ShouldOpenDownload() detects extension downloads based on the
   // characteristics of the download. Reconcile this. http://crbug.com/167702
@@ -384,7 +385,7 @@ bool ChromeDownloadManagerDelegate::ShouldCompleteDownload(
 
 bool ChromeDownloadManagerDelegate::ShouldOpenDownload(
     DownloadItem* item, const content::DownloadOpenDelayedCallback& callback) {
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   if (download_crx_util::IsExtensionDownload(*item) &&
       !extensions::WebstoreInstaller::GetAssociatedApproval(*item)) {
     scoped_refptr<extensions::CrxInstaller> crx_installer =
@@ -569,7 +570,7 @@ void ChromeDownloadManagerDelegate::NotifyExtensions(
     const base::FilePath& virtual_path,
     const NotifyExtensionsCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   extensions::ExtensionDownloadsEventRouter* router =
       DownloadServiceFactory::GetForBrowserContext(profile_)
           ->GetExtensionEventRouter();
@@ -751,7 +752,7 @@ void ChromeDownloadManagerDelegate::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   DCHECK_EQ(extensions::NOTIFICATION_CRX_INSTALLER_DONE, type);
 
   registrar_.Remove(this, extensions::NOTIFICATION_CRX_INSTALLER_DONE, source);