Remove Http2String wrapper for std::string.

gfe-relnote: n/a, no functional change.
PiperOrigin-RevId: 263816460
Change-Id: I4f365540414e6a3d78fd00ce6b39a4cdd4c14140
diff --git a/http2/hpack/decoder/hpack_block_collector.cc b/http2/hpack/decoder/hpack_block_collector.cc
index 1137be5..3490ca7 100644
--- a/http2/hpack/decoder/hpack_block_collector.cc
+++ b/http2/hpack/decoder/hpack_block_collector.cc
@@ -77,14 +77,14 @@
     HpackEntryType type,
     size_t index,
     bool value_huffman,
-    const Http2String& value) {
+    const std::string& value) {
   entries_.push_back(HpackEntryCollector(type, index, value_huffman, value));
 }
 void HpackBlockCollector::ExpectLiteralNameAndValue(HpackEntryType type,
                                                     bool name_huffman,
-                                                    const Http2String& name,
+                                                    const std::string& name,
                                                     bool value_huffman,
-                                                    const Http2String& value) {
+                                                    const std::string& value) {
   entries_.push_back(
       HpackEntryCollector(type, name_huffman, name, value_huffman, value));
 }