Convert enable_plugins to a buildflag header.

chrome/browser/ui/content_settings/content_setting_bubble_model.cc

Index: chrome/browser/ui/content_settings/content_setting_bubble_model.cc
diff --git a/chrome/browser/ui/content_settings/content_setting_bubble_model.cc b/chrome/browser/ui/content_settings/content_setting_bubble_model.cc
index 077761946b652adccdd5e8a1af6fa2be028068df..421b6e0cd2912cddad178074c8590fca0d60beb8 100644
--- a/chrome/browser/ui/content_settings/content_setting_bubble_model.cc
+++ b/chrome/browser/ui/content_settings/content_setting_bubble_model.cc
@@ -50,6 +50,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/origin_util.h"
+#include "ppapi/features/features.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/resources/grit/ui_resources.h"
@@ -559,7 +560,7 @@ void ContentSettingPluginBubbleModel::RunPluginsOnPage() {
   // settings bubble is visible.
   if (!web_contents())
     return;
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   // TODO(bauerb): We should send the identifiers of blocked plugins here.
   ChromePluginServiceFilter::GetInstance()->AuthorizeAllPlugins(
       web_contents(), true, std::string());