Moves QuicTag typedefs, and QuicTag utility methods to quic_tag.{h,cc}. No behavior change.

net/quic/core/quic_tag.cc

Index: net/quic/core/quic_tag.cc
diff --git a/net/quic/core/quic_tag.cc b/net/quic/core/quic_tag.cc
new file mode 100644
index 0000000000000000000000000000000000000000..584f582ebb49934d2563cbd3e9f06338fc6b03af
--- /dev/null
+++ b/net/quic/core/quic_tag.cc
@@ -0,0 +1,72 @@
+// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/quic/core/quic_tag.h"
+
+#include <algorithm>
+
+#include "base/macros.h"
+#include "base/strings/string_number_conversions.h"
+
+namespace net {
+
+bool FindMutualQuicTag(const QuicTagVector& our_tags_vector,
+                       const QuicTag* their_tags,
+                       size_t num_their_tags,
+                       QuicTag* out_result,
+                       size_t* out_index) {
+  if (our_tags_vector.empty()) {
+    return false;
+  }
+  const size_t num_our_tags = our_tags_vector.size();
+  for (size_t i = 0; i < num_our_tags; i++) {
+    for (size_t j = 0; j < num_their_tags; j++) {
+      if (our_tags_vector[i] == their_tags[j]) {
+        *out_result = our_tags_vector[i];
+        if (out_index != nullptr) {
+          *out_index = j;
+        }
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+std::string QuicTagToString(QuicTag tag) {
+  char chars[sizeof tag];
+  bool ascii = true;
+  const QuicTag orig_tag = tag;
+
+  for (size_t i = 0; i < arraysize(chars); i++) {
+    chars[i] = static_cast<char>(tag);
+    if ((chars[i] == 0 || chars[i] == '\xff') && i == arraysize(chars) - 1) {
+      chars[i] = ' ';
+    }
+    if (!isprint(static_cast<unsigned char>(chars[i]))) {
+      ascii = false;
+      break;
+    }
+    tag >>= 8;
+  }
+
+  if (ascii) {
+    return std::string(chars, sizeof(chars));
+  }
+
+  return base::UintToString(orig_tag);
+}
+
+uint32_t MakeQuicTag(char a, char b, char c, char d) {
+  return static_cast<uint32_t>(a) | static_cast<uint32_t>(b) << 8 |
+         static_cast<uint32_t>(c) << 16 | static_cast<uint32_t>(d) << 24;
+}
+
+bool ContainsQuicTag(const QuicTagVector& tag_vector, QuicTag tag) {
+  return std::find(tag_vector.begin(), tag_vector.end(), tag) !=
+         tag_vector.end();
+}
+
+}  // namespace net