Revert of Add a new enable_nonblocking_io field trial param for QUIC

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 309e6273e204d5e980bd4b4136a4bf8a6cbe84c1..1a956dee32e18f432642fb592f916905ed8cbb2f 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -1032,8 +1032,6 @@
       &params->quic_enable_truncated_connection_ids);
   globals.quic_enable_connection_racing.CopyToIfSet(
       &params->quic_enable_connection_racing);
-  globals.quic_enable_non_blocking_io.CopyToIfSet(
-      &params->quic_enable_non_blocking_io);
   globals.quic_disable_disk_cache.CopyToIfSet(
       &params->quic_disable_disk_cache);
   globals.quic_socket_receive_buffer_size.CopyToIfSet(
@@ -1180,8 +1178,6 @@
         ShouldQuicEnableTruncatedConnectionIds(quic_trial_params));
     globals->quic_enable_connection_racing.set(
         ShouldQuicEnableConnectionRacing(quic_trial_params));
-    globals->quic_enable_non_blocking_io.set(
-        ShouldQuicEnableNonBlockingIO(quic_trial_params));
     globals->quic_disable_disk_cache.set(
         ShouldQuicDisableDiskCache(quic_trial_params));
     globals->enable_quic_port_selection.set(
@@ -1389,14 +1385,6 @@
 }
 
 // static
-bool IOThread::ShouldQuicEnableNonBlockingIO(
-    const VariationParameters& quic_trial_params) {
-  return LowerCaseEqualsASCII(
-      GetVariationParam(quic_trial_params, "enable_non_blocking_io"),
-      "true");
-}
-
-// static
 bool IOThread::ShouldQuicDisableDiskCache(
     const VariationParameters& quic_trial_params) {
   return LowerCaseEqualsASCII(