Move libvpx from DEPS to src

WATCHLISTS

 # 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.
 
 # Watchlist Rules
 # Refer: http://dev.chromium.org/developers/contributing-code/watchlists
 
 # IMPORTANT: The regular expression filepath is tested against each path using
 # re.search, so it is not usually necessary to add .*.
 
@@ skipping 408 matching lines @@
     'ipc': {
       'filepath': 'ipc/ipc',
     },
     'ipc_messages': {
       'filepath': '_message.*.h|'\
                   '_messages.cc',
     },
     'libwebp': {
       'filepath': 'third_party/libwebp'
     },
+    'libvpx': {
+      'filepath': 'third_party/libvpx'
+    },
     'linux_fonts': {
       'filepath': 'ui/gfx/font_render_params_.*|'\
                   'ui/gfx/platform_font_linux.*|'\
                   'ui/gfx/render_text_harfbuzz.*',
     },
     'linux_sandboxing': {
       'filepath': 'sandbox/linux/',
     },
     'linux_seccomp_bpf': {
       'filepath': 'content/common/sandbox.*linux.cc',
@@ skipping 530 matching lines @@
     'installer': ['grt+watch@chromium.org', 'wfh+watch@chromium.org'],
     'installer_linux': [ 'mmoss@chromium.org'],
     'instant': ['dcblack@chromium.org', 'jered@chromium.org',
                 'samarth+watch@chromium.org', 'donnd+watch@chromium.org',
                 'melevin+watch@chromium.org', 'dougw+watch@chromium.org',
                 'kmadhusu+watch@chromium.org', 'dhollowa+watch@chromium.org',
                 'jfweitz+watch@chromium.org', 'skanuj+watch@chromium.org'],
     'ipc': ['jam@chromium.org', 'darin-cc@chromium.org'],
     'libwebp': ['urvang@chromium.org', 'jzern@chromium.org',
                 'skal@google.com', 'vikasa@google.com'],
+    'libvpx': ['tomfinegan@chromium.org', 'jzern@chromium.org',
+               'fgalligan@chromium.org', 'johannkoenig@chromium.org'],
     'linux_fonts': ['derat+watch@chromium.org'],
     'linux_sandboxing': ['jln+watch@chromium.org'],
     'linux_seccomp_bpf': ['jln+watch@chromium.org'],
     'supervised_users': ['pam+watch@chromium.org'],
     'mandoline': ['yzshen+watch@chromium.org'],
     'md_settings': ['jhawkins+watch-md-settings@chromium.org',
                     'jlklein+watch-md-settings@chromium.org',
                     'khorimoto+watch-md-settings@chromium.org',
                     'michaelpg+watch-md-settings@chromium.org',
                     'orenb+watch-md-settings@chromium.org',
@@ skipping 115 matching lines @@
                      'posciak+watch@chromium.org'],
     'website_settings': ['markusheintz@chromium.org'],
     'windows_sandboxing': ['wfh+watch@chromium.org'],
     'worker': ['jam@chromium.org'],
     'x11': ['derat+watch@chromium.org',
             'sadrul@chromium.org',
             'yusukes+watch@chromium.org'],
     'zoom': ['wjmaclean@chromium.org'],
   },
 }