fix build when ffmpeg, libvpx and libwebm are disabled

build/gn_migration.gypi

 # Copyright (c) 2015 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.
 
 # This file defines five targets that we are using to track the progress of the
 # GYP->GN migration:
 #
 # 'both_gn_and_gyp' lists what GN is currently capable of building and should
 # match the 'both_gn_and_gyp' target in //BUILD.gn.
 #
 # 'gyp_all' Should include everything built when building "all"; i.e., if you
 # type 'ninja gyp_all' and then 'ninja all', the second build should do
 # nothing. 'gyp_all' should just depend on the other four targets.
 #
 # 'gyp_remaining' lists all of the targets that still need to be converted,
 # i.e., all of the other (non-empty) targets that a GYP build will build.
 #
 # TODO(GYP): crbug.com/481694. Add a build step to the bot that enforces the
 # above contracts.
 
 {
+  'includes': [
+    '../media/media_variables.gypi'
+  ],
   'targets': [
     {
       'target_name': 'gyp_all',
       'type': 'none',
       'dependencies': [
         'both_gn_and_gyp',
         'gyp_remaining',
       ]
     },
     {
@@ skipping 321 matching lines @@
             '../chrome/chrome.gyp:performance_browser_tests',
             '../chrome/chrome.gyp:sync_integration_tests',
             '../chrome/chrome.gyp:sync_performance_tests',
             '../chrome/tools/profile_reset/jtl_compiler.gyp:jtl_compiler',
             '../extensions/extensions_tests.gyp:extensions_browsertests',
             '../extensions/extensions_tests.gyp:extensions_unittests',
             '../gin/gin.gyp:gin_shell',
             '../gpu/gles2_conform_support/gles2_conform_test.gyp:gles2_conform_test',  # TODO(GYP) crbug.com/471920
             '../gpu/khronos_glcts_support/khronos_glcts_test.gyp:khronos_glcts_test',  # TODO(GYP) crbug.com/471903 to make this complete.
             '../ipc/ipc.gyp:ipc_perftests',
-            '../media/media.gyp:ffmpeg_regression_tests',  # TODO(GYP) this should be conditional on media_use_ffmpeg
             '../mojo/mojo_base.gyp:mojo_common_unittests',
             '../ppapi/tools/ppapi_tools.gyp:pepper_hash_for_uma',
             '../skia/skia.gyp:filter_fuzz_stub',
             '../skia/skia.gyp:image_operations_bench',
             '../sync/tools/sync_tools.gyp:sync_client',
             '../sync/tools/sync_tools.gyp:sync_listen_notifications',
             '../third_party/codesighs/codesighs.gyp:codesighs',
             '../third_party/codesighs/codesighs.gyp:maptsvdifftool',
             '../third_party/pdfium/samples/samples.gyp:pdfium_diff',
             '../third_party/pdfium/samples/samples.gyp:pdfium_test',
             '../tools/gn/gn.gyp:generate_test_gn_data',
             '../tools/gn/gn.gyp:gn',
             '../tools/gn/gn.gyp:gn_unittests',
             '../tools/perf/clear_system_cache/clear_system_cache.gyp:clear_system_cache',
             '../ui/message_center/message_center.gyp:message_center_unittests',
             '../ui/views/examples/examples.gyp:views_examples_with_content_exe',
           ],
         }],
+        ['media_use_ffmpeg==1', {
+          'dependencies': [
+            '../media/media.gyp:ffmpeg_regression_tests',
+          ],
+        }],
         ['OS=="android" or OS=="linux"', {
           'dependencies': [
             '../net/net.gyp:disk_cache_memory_test',
           ],
         }],
         ['chromeos==1', {
           'dependencies': [
             '../chromeos/chromeos.gyp:chromeos_unittests',
             '../ui/chromeos/ui_chromeos.gyp:ui_chromeos_unittests',
           ]
@@ skipping 396 matching lines @@
         ['OS=="android" and target_arch != "x64"', {
           'dependencies': [
             '../third_party/android_platform/relocation_packer.gyp:android_relocation_packer_unittests#host'
           ],
         }],
       ],
     },
   ]
 }