Convert enable_plugins to a buildflag header.

chrome/browser/extensions/extension_service_unittest.cc

Index: chrome/browser/extensions/extension_service_unittest.cc
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index d45bee37200825ffb07eadc55a1019dee006db84..744a4faa68d086bca754c3b618fca2c1cc450389 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -132,6 +132,7 @@
 #include "net/cookies/cookie_store.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "ppapi/features/features.h"
 #include "storage/browser/database/database_tracker.h"
 #include "storage/browser/quota/quota_manager.h"
 #include "storage/common/database/database_identifier.h"
@@ -759,7 +760,7 @@ class ExtensionServiceTest
   }
 
   void InitPluginService() {
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
     PluginService::GetInstance()->Init();
 #endif
   }
@@ -5623,7 +5624,7 @@ class ExtensionServiceTestSimple : public testing::Test {
 TEST_F(ExtensionServiceTestSimple, Enabledness) {
   // Make sure the PluginService singleton is destroyed at the end of the test.
   base::ShadowingAtExitManager at_exit_manager;
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   content::PluginService::GetInstance()->Init();
 #endif