Replace QuicString with std::string, pass 1

This replaces QuicString with std::string in all of the "QUIC proper".  I will
delete QuicString once all code using it is gone.

gfe-relnote: n/a (no functional change)
PiperOrigin-RevId: 237872023
Change-Id: I82de62c9855516b15039734d05155917e68ff4ee
diff --git a/quic/core/http/spdy_utils_test.cc b/quic/core/http/spdy_utils_test.cc
index 6cd2f1d..5e6fbbf 100644
--- a/quic/core/http/spdy_utils_test.cc
+++ b/quic/core/http/spdy_utils_test.cc
@@ -39,7 +39,7 @@
                            {"cookie", "part3"},
 
                            // Already-delimited headers are passed through.
-                           {"passed-through", QuicString("foo\0baz", 7)},
+                           {"passed-through", std::string("foo\0baz", 7)},
 
                            // Other headers are joined on \0.
                            {"joined", "value 1"},
@@ -374,7 +374,7 @@
 using PopulateHeaderBlockFromUrl = QuicTest;
 
 TEST_F(PopulateHeaderBlockFromUrl, NormalUsage) {
-  QuicString url = "https://www.google.com/index.html";
+  std::string url = "https://www.google.com/index.html";
   SpdyHeaderBlock headers;
   EXPECT_TRUE(SpdyUtils::PopulateHeaderBlockFromUrl(url, &headers));
   EXPECT_EQ("https", headers[":scheme"].as_string());
@@ -383,7 +383,7 @@
 }
 
 TEST_F(PopulateHeaderBlockFromUrl, UrlWithNoPath) {
-  QuicString url = "https://www.google.com";
+  std::string url = "https://www.google.com";
   SpdyHeaderBlock headers;
   EXPECT_TRUE(SpdyUtils::PopulateHeaderBlockFromUrl(url, &headers));
   EXPECT_EQ("https", headers[":scheme"].as_string());