Revert of 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 1a956dee32e18f432642fb592f916905ed8cbb2f..309e6273e204d5e980bd4b4136a4bf8a6cbe84c1 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -1032,6 +1032,8 @@
       &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(
@@ -1178,6 +1180,8 @@
         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(
@@ -1385,6 +1389,14 @@
 }
 
 // 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(