Remove quiche::QuicheStringPiece and quiche::QuicheStringPieceHash.

Also replace some MOCK_METHOD1 with MOCK_METHOD to make the linter happy.

PiperOrigin-RevId: 336909722
Change-Id: I68bcc1a674815934fb271870eac2dff9028d980d
diff --git a/http2/hpack/decoder/hpack_string_collector.cc b/http2/hpack/decoder/hpack_string_collector.cc
index b9feb48..8300d57 100644
--- a/http2/hpack/decoder/hpack_string_collector.cc
+++ b/http2/hpack/decoder/hpack_string_collector.cc
@@ -66,7 +66,7 @@
 }
 
 void HpackStringCollector::OnStringData(const char* data, size_t length) {
-  quiche::QuicheStringPiece sp(data, length);
+  absl::string_view sp(data, length);
   EXPECT_TRUE(IsInProgress()) << ToString();
   EXPECT_LE(sp.size(), len) << ToString();
   Http2StrAppend(&s, sp);
@@ -80,7 +80,7 @@
 }
 
 ::testing::AssertionResult HpackStringCollector::Collected(
-    quiche::QuicheStringPiece str,
+    absl::string_view str,
     bool is_huffman_encoded) const {
   VERIFY_TRUE(HasEnded());
   VERIFY_EQ(str.size(), len);