Remove GYP files.

third_party/libwebm/libwebm.gyp

Index: third_party/libwebm/libwebm.gyp
diff --git a/third_party/libwebm/libwebm.gyp b/third_party/libwebm/libwebm.gyp
deleted file mode 100644
index b31881585825e2547fd10d4526916fea7e204719..0000000000000000000000000000000000000000
--- a/third_party/libwebm/libwebm.gyp
+++ /dev/null
@@ -1,32 +0,0 @@
-# Copyright 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.
-
-{
-  'targets': [
-    {
-      'target_name': 'libwebm',
-      'type': 'static_library',
-      'conditions': [
-        ['OS!="win"', {
-          'cflags': [
-            '-Wno-deprecated-declarations',  # libwebm uses std::auto_ptr
-          ],
-        }],
-      ],
-      'include_dirs': [
-        './source',
-      ],
-      'direct_dependent_settings': {
-        'include_dirs': [
-          './source',
-        ],
-      },
-      'sources': [
-        'source/mkvmuxer/mkvmuxer.cc',
-        'source/mkvmuxer/mkvmuxerutil.cc',
-        'source/mkvmuxer/mkvwriter.cc',
-      ],
-    },  # target libwebm
-  ]
-}