Convert enable_plugins to a buildflag header.

chrome/browser/renderer_context_menu/render_view_context_menu.h

Index: chrome/browser/renderer_context_menu/render_view_context_menu.h
diff --git a/chrome/browser/renderer_context_menu/render_view_context_menu.h b/chrome/browser/renderer_context_menu/render_view_context_menu.h
index 302cf17462d24c97103eefdc74579887760684e4..846f5c2234655a4e345532d65c6b1cbac72b2a39 100644
--- a/chrome/browser/renderer_context_menu/render_view_context_menu.h
+++ b/chrome/browser/renderer_context_menu/render_view_context_menu.h
@@ -21,6 +21,7 @@
 #include "components/renderer_context_menu/render_view_context_menu_proxy.h"
 #include "content/public/common/context_menu_params.h"
 #include "extensions/features/features.h"
+#include "ppapi/features/features.h"
 #include "printing/features/features.h"
 #include "ui/base/models/simple_menu_model.h"
 #include "ui/base/window_open_disposition.h"
@@ -117,7 +118,7 @@ class RenderViewContextMenu : public RenderViewContextMenuBase {
   // RenderViewContextMenuBase:
   void InitMenu() override;
   void RecordShownItem(int id) override;
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   void HandleAuthorizeAllPlugins() override;
 #endif
   void NotifyMenuShown() override;