Protobuf for Traffic Annotation and first use by a URLFetcher.

tools/traffic_annotation/sample_traffic_annotation.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 "net/traffic_annotation/network_traffic_annotation.h"
+
+// This file includes a sample and a template for text-coded traffic_annotation.
+// For more description on each field, please refer to:
+// (tools/traffic_annotation/traffic_annotation.proto)
+// For more information on policies, please refer to:
+// http://dev.chromium.org/administrators/policy-list-3
+
+void network_traffic_annotation_sample() {
+  net::NetworkTrafficAnnotationTag traffic_annotation =
+      net::DefineNetworkTrafficAnnotation("spellcheck_lookup", R"(
+        semantics {
+          sender: "spellcheck"
+          description:
+            "Google Chrome can provide smarter spell-checking by sending "
+            "text you type into the browser to Google's servers, allowing "
+            "you to use the same spell-checking technology used by Google "
+            "products, such as Docs. If the feature is enabled, Chrome will "
+            "send the entire contents of text fields as you type in them to "
+            "Google along with the browser’s default language. Google "
+            "returns a list of suggested spellings, which will be displayed "
+            "in the context menu."
+          trigger: "User types text into a text field or asks to correct a "
+                   "misspelled word."
+          data: "Text a user has typed into a text field. No user identifier "
+                "is sent along with the text."
+          destination: GOOGLE_OWNED_SERVICE
+        }
+        policy {
+          cookies_allowed: false
+          setting:
+            "You can enable or disable this feature via 'Use a web service to "
+            "help resolve spelling errors.' in Chrome's settings under "
+            "Advanced. The feature is disabled by default."
+          policy {
+            SpellCheckServiceEnabled {
+                policy_options {mode: MANDATORY}
+                value: false
+            }
+          }
+        })");
+}
+
+void network_traffic_annotation_template() {
+  net::NetworkTrafficAnnotationTag traffic_annotation =
+      net::DefineNetworkTrafficAnnotation("", R"(
+        semantics {
+          sender: ""
+          description: ""
+          trigger: ""
+          data: ""
+          destination: WEBSITE/GOOGLE_OWNED_SERVICE/OTHER
+        }
+        policy {
+          cookies_allowed: false/true
+          cookies_store: ""
+          setting: ""
+          policy {
+            [POLICY_NAME] {
+                policy_options {mode: MANDATORY/RECOMMENDED/UNSET}
+                value: ...
+            }
+          }
+        })");
+}