Fix all Performance and Bug-Prone patterns in quic/core. No functional change. Not flag protected.

net/tools/quic/end_to_end_test.cc

Index: net/tools/quic/end_to_end_test.cc
diff --git a/net/tools/quic/end_to_end_test.cc b/net/tools/quic/end_to_end_test.cc
index 4988cc428c41f39a80530f74946aaa72f9035740..127fec715248cd5776f1a69ccd5233e2784b6d27 100644
--- a/net/tools/quic/end_to_end_test.cc
+++ b/net/tools/quic/end_to_end_test.cc
@@ -2165,7 +2165,8 @@ class ServerStreamWithErrorResponseBody : public QuicSimpleServerStream {
   ServerStreamWithErrorResponseBody(QuicStreamId id,
                                     QuicSpdySession* session,
                                     string response_body)
-      : QuicSimpleServerStream(id, session), response_body_(response_body) {}
+      : QuicSimpleServerStream(id, session),
+        response_body_(std::move(response_body)) {}
 
   ~ServerStreamWithErrorResponseBody() override {}
 
@@ -2187,7 +2188,7 @@ class ServerStreamWithErrorResponseBody : public QuicSimpleServerStream {
 class StreamWithErrorFactory : public QuicTestServer::StreamFactory {
  public:
   explicit StreamWithErrorFactory(string response_body)
-      : response_body_(response_body) {}
+      : response_body_(std::move(response_body)) {}
 
   ~StreamWithErrorFactory() override {}
 
@@ -2623,7 +2624,7 @@ TEST_P(EndToEndTestServerPush, ServerPushUnderLimit) {
   EXPECT_EQ(kBody, client_->SendSynchronousRequest(
                        "https://example.com/push_example"));
 
-  for (string url : push_urls) {
+  for (const string& url : push_urls) {
     // Sending subsequent requesets will not actually send anything on the wire,
     // as the responses are already in the client's cache.
     DVLOG(1) << "send request for pushed stream on url " << url;