Deprecate FLAGS_quic_enable_arena_allocation.

net/quic/quic_flags.cc

Index: net/quic/quic_flags.cc
diff --git a/net/quic/quic_flags.cc b/net/quic/quic_flags.cc
index 148aa094f2fa1ce3828a484601b6b9f2a5ec2a62..0d0a5c3c02ea7b459b34e1cee1a14464dcb8647d 100644
--- a/net/quic/quic_flags.cc
+++ b/net/quic/quic_flags.cc
@@ -78,10 +78,6 @@ bool FLAGS_quic_general_loss_algorithm = true;
 // considered to be caused by NATs.
 bool FLAGS_quic_disable_non_nat_address_migration = true;
 
-// If true, QuicOneBlockArenas will allocate out of their local memory.
-// Otherwise, they will always use the heap.
-bool FLAGS_quic_enable_arena_allocation = true;
-
 // If true, QUIC connections will timeout when packets are not being recieved,
 // even if they are being sent.
 bool FLAGS_quic_use_new_idle_timeout = true;