Convert enable_plugins to a buildflag header.

chrome/renderer/chrome_content_renderer_client.h

Index: chrome/renderer/chrome_content_renderer_client.h
diff --git a/chrome/renderer/chrome_content_renderer_client.h b/chrome/renderer/chrome_content_renderer_client.h
index 4f7bbbbc2eed67563eea118cd95dd09fc8a3a1f9..09377ed8221b236ea98eb79124dfe5f3f3f8695e 100644
--- a/chrome/renderer/chrome_content_renderer_client.h
+++ b/chrome/renderer/chrome_content_renderer_client.h
@@ -21,6 +21,7 @@
 #include "content/public/renderer/content_renderer_client.h"
 #include "extensions/features/features.h"
 #include "ipc/ipc_channel_proxy.h"
+#include "ppapi/features/features.h"
 #include "printing/features/features.h"
 #include "v8/include/v8.h"
 
@@ -193,7 +194,7 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
   void SetSpellcheck(SpellCheck* spellcheck);
 #endif
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   static blink::WebPlugin* CreatePlugin(
       content::RenderFrame* render_frame,
       blink::WebLocalFrame* frame,
@@ -201,7 +202,7 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
       const ChromeViewHostMsg_GetPluginInfo_Output& output);
 #endif
 
-#if defined(ENABLE_PLUGINS) && BUILDFLAG(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_PLUGINS) && BUILDFLAG(ENABLE_EXTENSIONS)
   static bool IsExtensionOrSharedModuleWhitelisted(
       const GURL& url, const std::set<std::string>& whitelist);
 #endif
@@ -249,7 +250,7 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
 #if BUILDFLAG(ENABLE_PRINT_PREVIEW)
   std::unique_ptr<ChromePDFPrintClient> pdf_print_client_;
 #endif
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   std::set<std::string> allowed_camera_device_origins_;
   std::set<std::string> allowed_compositor_origins_;
 #endif