Move enable extensions define to a build flag.

chrome/browser/download/download_target_determiner_unittest.cc

Index: chrome/browser/download/download_target_determiner_unittest.cc
diff --git a/chrome/browser/download/download_target_determiner_unittest.cc b/chrome/browser/download/download_target_determiner_unittest.cc
index b050b361c2840af3e09181729749df49a26b5939..ca44f4c00888594245deb73de26ba3690070c565 100644
--- a/chrome/browser/download/download_target_determiner_unittest.cc
+++ b/chrome/browser/download/download_target_determiner_unittest.cc
@@ -37,6 +37,7 @@
 #include "content/public/test/mock_download_item.h"
 #include "content/public/test/test_renderer_host.h"
 #include "content/public/test/web_contents_tester.h"
+#include "extensions/features/features.h"
 #include "net/base/mime_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -48,7 +49,7 @@
 #include "content/public/common/webplugininfo.h"
 #endif
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "extensions/common/extension.h"
 #endif
 
@@ -1213,7 +1214,7 @@ TEST_F(DownloadTargetDeterminerTest, PromptAlways) {
 }
 #endif  // !BUILDFLAG(ANDROID_JAVA_UI)
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 // These test cases are run with "Prompt for download" user preference set to
 // true. Automatic extension downloads shouldn't cause prompting.
 // Android doesn't support extensions.
@@ -1259,7 +1260,7 @@ TEST_F(DownloadTargetDeterminerTest, PromptAlways_Extension) {
   RunTestCasesWithActiveItem(kPromptingTestCases,
                              arraysize(kPromptingTestCases));
 }
-#endif  // defined(ENABLE_EXTENSIONS)
+#endif  // BUILDFLAG(ENABLE_EXTENSIONS)
 
 // If the download path is managed, then we don't show any prompts.
 // Note that if the download path is managed, then PromptForDownload() is false.