Remove unnecessary QuicStreamPeer methods.

These methods access QuicStream methods that are already public, or
QuicStream members that already have public accessors.

NO_BUG=trivial refactor

gfe-relnote: n/a.  No functional change.  Test-only change.
PiperOrigin-RevId: 243831754
Change-Id: Id774f61e98b170320279b293a60db63ccf11035a
diff --git a/quic/core/quic_session_test.cc b/quic/core/quic_session_test.cc
index eb76c95..8020de5 100644
--- a/quic/core/quic_session_test.cc
+++ b/quic/core/quic_session_test.cc
@@ -2329,7 +2329,7 @@
   TestStream* stream = session_.CreateOutgoingBidirectionalStream();
 
   // Ensure that the stream starts out open in both directions.
-  EXPECT_FALSE(QuicStreamPeer::write_side_closed(stream));
+  EXPECT_FALSE(stream->write_side_closed());
   EXPECT_FALSE(QuicStreamPeer::read_side_closed(stream));
 
   QuicStreamId stream_id = stream->id();
@@ -2344,7 +2344,7 @@
   // When the STOP_SENDING is received, the node generates a RST_STREAM,
   // which closes the stream in the write direction. Ensure this.
   EXPECT_FALSE(QuicStreamPeer::read_side_closed(stream));
-  EXPECT_TRUE(QuicStreamPeer::write_side_closed(stream));
+  EXPECT_TRUE(stream->write_side_closed());
 }
 
 }  // namespace