Protobuf for Traffic Annotation and first use by a URLFetcher.

net/BUILD.gn

Index: net/BUILD.gn
diff --git a/net/BUILD.gn b/net/BUILD.gn
index 73d7b1e2b8b34da1a5a573f55346ee9cb53c5ebb..f4240edc6a7c747b4b9bfb105500f4bb425cf2de 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -2964,6 +2964,13 @@ source_set("simple_quic_tools") {
   ]
 }
 
+source_set("traffic_annotation_header") {

[asanka, 2017/01/26 20:59:27]

why is this in a separate source set when url_fetcher.h and
url_request_context.h depends on it?

[Ramin Halavati, 2017/01/27 07:48:58]

I separated it so that tools that just use annotation definition, like the ones
that analyze annotations, create reports, check policy definitions, etc., won't
need to define a dependency on the whole net. But it can be done the other way
as well if you see that a better choice.

[asanka, 2017/01/27 16:58:00]

Got it.

Can you add :traffic_annotation_header (or rename it to traffic_annotation since
the fact that it's a header isn't important to net) to the |deps| of the source
sets that depend on it?

[Ramin Halavati, 2017/01/30 08:43:25]

Done, renamed it to traffic_annotation and added it "net" component" which was
the only source set having url_fetcher or url_requestion_context.

+  sources = [
+    "net/traffic_annotation/network_traffic_annotation.h",
+  ]
+  deps = []
+}
+
 if (!is_ios) {
   executable("quic_client") {
     sources = [