Factor the QuicDispatcher's blocked writer list into a stand-alone
QuicBlockedWriterList.

PiperOrigin-RevId: 627519607
diff --git a/build/source_list.json b/build/source_list.json
index 191c426..38d2b75 100644
--- a/build/source_list.json
+++ b/build/source_list.json
@@ -274,6 +274,7 @@
     "quiche/quic/core/quic_arena_scoped_ptr.h",
     "quiche/quic/core/quic_bandwidth.h",
     "quiche/quic/core/quic_blocked_writer_interface.h",
+    "quiche/quic/core/quic_blocked_writer_list.h",
     "quiche/quic/core/quic_buffered_packet_store.h",
     "quiche/quic/core/quic_chaos_protector.h",
     "quiche/quic/core/quic_clock.h",
@@ -605,6 +606,7 @@
     "quiche/quic/core/quic_ack_listener_interface.cc",
     "quiche/quic/core/quic_alarm.cc",
     "quiche/quic/core/quic_bandwidth.cc",
+    "quiche/quic/core/quic_blocked_writer_list.cc",
     "quiche/quic/core/quic_buffered_packet_store.cc",
     "quiche/quic/core/quic_chaos_protector.cc",
     "quiche/quic/core/quic_coalesced_packet.cc",
@@ -1239,6 +1241,7 @@
     "quiche/quic/core/quic_alarm_test.cc",
     "quiche/quic/core/quic_arena_scoped_ptr_test.cc",
     "quiche/quic/core/quic_bandwidth_test.cc",
+    "quiche/quic/core/quic_blocked_writer_list_test.cc",
     "quiche/quic/core/quic_buffered_packet_store_test.cc",
     "quiche/quic/core/quic_chaos_protector_test.cc",
     "quiche/quic/core/quic_coalesced_packet_test.cc",