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/http/end_to_end_test.cc b/quic/core/http/end_to_end_test.cc
index 753b951..e537c73 100644
--- a/quic/core/http/end_to_end_test.cc
+++ b/quic/core/http/end_to_end_test.cc
@@ -3780,8 +3780,7 @@
   client_->SendMessage(headers, "", /*fin=*/false);
   // Stream should be open
   ASSERT_NE(nullptr, client_->latest_created_stream());
-  EXPECT_FALSE(
-      QuicStreamPeer::write_side_closed(client_->latest_created_stream()));
+  EXPECT_FALSE(client_->latest_created_stream()->write_side_closed());
   EXPECT_FALSE(
       QuicStreamPeer::read_side_closed(client_->latest_created_stream()));