Disable NaCl browser_tests for GN builds.

chrome/browser/extensions/api/media_galleries/media_galleries_apitest.cc

 // 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.
 
 #include "base/auto_reset.h"
 #include "base/callback.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/json/json_writer.h"
 #include "base/numerics/safe_conversions.h"
@@ skipping 419 matching lines @@
     runloop.Run();
     return preferences;
   }
 
   std::string device_id_;
   base::ScopedTempDir fake_gallery_temp_dir_;
   int test_jpg_size_;
   scoped_ptr<EnsureMediaDirectoriesExists> ensure_media_directories_exists_;
 };
 
-#if !defined(DISABLE_NACL)
+#if !defined(DISABLE_NACL) && !defined(DISABLE_NACL_BROWSERTESTS)
 class MediaGalleriesPlatformAppPpapiTest
     : public MediaGalleriesPlatformAppBrowserTest {
  protected:
   void SetUpCommandLine(base::CommandLine* command_line) override {
     MediaGalleriesPlatformAppBrowserTest::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kEnablePepperTesting);
   }
 
   void SetUpOnMainThread() override {
     MediaGalleriesPlatformAppBrowserTest::SetUpOnMainThread();
@@ skipping 226 matching lines @@
 
   base::ListValue custom_args;
 #if defined(USE_PROPRIETARY_CODECS)
   custom_args.AppendBoolean(true);
 #else
   custom_args.AppendBoolean(false);
 #endif
   ASSERT_TRUE(RunMediaGalleriesTestWithArg("media_metadata", custom_args))
       << message_;
 }