Delete I420 encoder and decoder.

webrtc/modules/video_coding/BUILD.gn

Index: webrtc/modules/video_coding/BUILD.gn
diff --git a/webrtc/modules/video_coding/BUILD.gn b/webrtc/modules/video_coding/BUILD.gn
index bc6f595b51d16c5570fac2690016095bcd4da0b7..1a9697409e9d83df2b61d5bb9ec9689871310e22 100644
--- a/webrtc/modules/video_coding/BUILD.gn
+++ b/webrtc/modules/video_coding/BUILD.gn
@@ -94,7 +94,6 @@ source_set("video_coding") {
   deps = [
     ":video_coding_utility",
     ":webrtc_h264",
-    ":webrtc_i420",
     ":webrtc_vp8",
     ":webrtc_vp9",
     "../..:webrtc_common",
@@ -172,26 +171,6 @@ source_set("webrtc_h264") {
 # TODO(tkchin): Source set for webrtc_h264_video_toolbox. Currently not
 # possible to add, see https://crbug.com/297668.
 
-source_set("webrtc_i420") {
-  sources = [
-    "codecs/i420/i420.cc",
-    "codecs/i420/include/i420.h",
-  ]
-
-  configs += [ "../..:common_config" ]
-  public_configs = [ "../..:common_inherited_config" ]
-
-  if (is_clang) {
-    # Suppress warnings from Chrome's Clang plugins.
-    # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
-    configs -= [ "//build/config/clang:find_bad_constructs" ]
-  }
-
-  deps = [
-    "../../system_wrappers",
-  ]
-}
-
 source_set("webrtc_vp8") {
   sources = [
     "codecs/vp8/default_temporal_layers.cc",