Remove all references to GYP

webrtc/supplement.gypi

-{
-  'variables': {
-    'variables': {
-      'webrtc_root%': '<(DEPTH)/webrtc',
-      # Override the defaults in Chromium's build/common.gypi.
-      # Needed for ARC and libc++.
-      'mac_sdk_min%': '10.11',
-      'mac_deployment_target%': '10.7',
-    },
-    'webrtc_root%': '<(webrtc_root)',
-    'mac_deployment_target%': '<(mac_deployment_target)',
-    'use_sysroot%': '<(use_sysroot)',
-    'build_with_chromium': 0,
-    'conditions': [
-      ['OS=="ios"', {
-        # Set target_subarch for if not already set. This is needed because the
-        # Chromium iOS toolchain relies on target_subarch being set.
-        'conditions': [
-          ['target_arch=="arm" or target_arch=="ia32"', {
-            'target_subarch%': 'arm32',
-          }],
-          ['target_arch=="arm64" or target_arch=="x64"', {
-            'target_subarch%': 'arm64',
-          }],
-        ],
-      }],
-      ['OS=="android"', {
-        # MJPEG capture is not used on Android. Disable to reduce
-        # libjingle_peerconnection_so file size.
-        'libyuv_disable_jpeg%': 1,
-      }],
-    ],
-  },
-  'target_defaults': {
-    'target_conditions': [
-      ['_target_name=="sanitizer_options"', {
-        'conditions': [
-          ['lsan==1', {
-            # Replace Chromium's LSan suppressions with our own for WebRTC.
-            'sources/': [
-              ['exclude', 'lsan_suppressions.cc'],
-            ],
-            'sources': [
-              '<(webrtc_root)/build/sanitizers/lsan_suppressions_webrtc.cc',
-            ],
-          }],
-          ['tsan==1', {
-            # Replace Chromium's TSan v2 suppressions with our own for WebRTC.
-            'sources/': [
-              ['exclude', 'tsan_suppressions.cc'],
-            ],
-            'sources': [
-              '<(webrtc_root)/build/sanitizers/tsan_suppressions_webrtc.cc',
-            ],
-          }],
-        ],
-      }],
-    ],
-  },
-}