Convert enable_plugins to a buildflag header.

chrome/browser/chrome_content_browser_client.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROME_CONTENT_BROWSER_CLIENT_H_
 #define CHROME_BROWSER_CHROME_CONTENT_BROWSER_CLIENT_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "build/build_config.h"
 #include "content/public/browser/content_browser_client.h"
 #include "extensions/features/features.h"
 #include "media/media_features.h"
+#include "ppapi/features/features.h"
 
 class ChromeContentBrowserClientParts;
 
 namespace base {
 class CommandLine;
 }
 
 namespace content {
 class BrowserContext;
 class QuotaPermissionContext;
@@ skipping 312 matching lines @@
       bool allow);
 
   static void RequestFileSystemPermissionOnUIThread(
       int render_process_id,
       int render_frame_id,
       const GURL& url,
       bool allowed_by_default,
       const base::Callback<void(bool)>& callback);
 #endif
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   // Set of origins that can use TCP/UDP private APIs from NaCl.
   std::set<std::string> allowed_socket_origins_;
   // Set of origins that can get a handle for FileIO from NaCl.
   std::set<std::string> allowed_file_handle_origins_;
   // Set of origins that can use "dev chanel" APIs from NaCl, even on stable
   // versions of Chrome.
   std::set<std::string> allowed_dev_channel_origins_;
 #endif
 
   // Vector of additional ChromeContentBrowserClientParts.
   // Parts are deleted in the reverse order they are added.
   std::vector<ChromeContentBrowserClientParts*> extra_parts_;
 
   base::WeakPtrFactory<ChromeContentBrowserClient> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentBrowserClient);
 };
 
 #endif  // CHROME_BROWSER_CHROME_CONTENT_BROWSER_CLIENT_H_