Make FuzzedDataProvider vend std::strings

net/websockets/websocket_frame_parser_fuzzer.cc

Index: net/websockets/websocket_frame_parser_fuzzer.cc
diff --git a/net/websockets/websocket_frame_parser_fuzzer.cc b/net/websockets/websocket_frame_parser_fuzzer.cc
index 562941dfdad1c0787f08a5627f00907e0cc92072..5320af4b5d8d8eb6663e467a6e569939b145cd86 100644
--- a/net/websockets/websocket_frame_parser_fuzzer.cc
+++ b/net/websockets/websocket_frame_parser_fuzzer.cc
@@ -17,7 +17,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   std::vector<std::unique_ptr<net::WebSocketFrameChunk>> frame_chunks;
   while (fuzzed_data_provider.remaining_bytes() > 0) {
     size_t chunk_size = fuzzed_data_provider.ConsumeUint32InRange(1, 32);
-    base::StringPiece chunk = fuzzed_data_provider.ConsumeBytes(chunk_size);
+    std::string chunk = fuzzed_data_provider.ConsumeBytes(chunk_size);
     parser.Decode(chunk.data(), chunk.size(), &frame_chunks);
   }
   return 0;