Syntax and coverage checking added to Network Traffic Annotations.

chrome/browser/net/traffic_annotation/network_traffic_annotation_checker.cc

+// Copyright 2017 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 "chrome/browser/net/traffic_annotation/network_traffic_annotation_checker.h"
+
+#include "base/logging.h"
+
+namespace {}
+
+NetworkTrafficAnnotationChecker::NetworkTrafficAnnotationChecker() {}
+
+NetworkTrafficAnnotationChecker::~NetworkTrafficAnnotationChecker() {}
+
+void NetworkTrafficAnnotationChecker::CheckAnnotation(
+    const net::NetworkTrafficAnnotationTag& traffic_annotation) {
+#if defined(_DEBUG) || defined(DCHECK_ALWAYS_ON)
+  if (visited_annotations_.find(traffic_annotation.unique_id) !=
+      visited_annotations_.end())
+    return;
+
+  bool syntax_checked = false;
+  // Check if unique_id/content pair is unique.
+  for (const auto& other_annotation : visited_annotations_) {
+    if (!strcmp(other_annotation.first, traffic_annotation.unique_id)) {
+      if (!strcmp(other_annotation.second, traffic_annotation.proto)) {
+        // For some reason, there are more than one copie of one pair.
+        DLOG(WARNING)
+            << "Traffic other_annotation comes from multiple sources: "
+            << traffic_annotation.unique_id;
+        syntax_checked = true;
+        break;
+      } else {
+        DLOG(ERROR)
+            << "Traffic other_annotation unique id with multiple protos: "
+            << traffic_annotation.unique_id;
+      }
+    }
+  }
+  // Check if content syntax is correct and complete.
+  if (!syntax_checked) {
+    // Proto stuff.
+  }
+
+  // Add it to the list.
+  visited_annotations_.insert(
+      std::make_pair(traffic_annotation.unique_id, traffic_annotation.proto));
+#endif
+}