Create component to expose network usage stats to consumers.

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index ac24cd6912b3a713943af2960c79113cd1874e16..478335a8015a5663eb7ea0dde73fa21bedc866dc 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -40,6 +40,7 @@
 #include "chrome/common/pref_names.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_prefs.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
+#include "components/data_usage/core/data_use_aggregator.h"
 #include "components/net_log/chrome_net_log.h"
 #include "components/policy/core/common/policy_service.h"
 #include "components/proxy_config/pref_proxy_config_tracker.h"
@@ -567,6 +568,8 @@ void IOThread::Init() {
       extension_event_router_forwarder_;
 #endif
 
+  globals_->data_use_aggregator.reset(new data_usage::DataUseAggregator());
+
   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
   // is fixed.
   tracked_objects::ScopedTracker tracking_profile3(
@@ -575,6 +578,10 @@ void IOThread::Init() {
   scoped_ptr<ChromeNetworkDelegate> chrome_network_delegate(
       new ChromeNetworkDelegate(extension_event_router_forwarder(),
                                 &system_enable_referrers_));
+  // By default, data usage is considered off the record.
+  chrome_network_delegate->set_data_use_aggregator(
+      globals_->data_use_aggregator.get(),
+      true /* is_data_usage_off_the_record */);

[bengr, 2015/10/06 19:30:27]

Why the underscores?

[sclittle, 2015/10/07 01:07:55]

Because that's what the argument name is, |is_data_usage_off_the_record|.

[tbansal1, 2015/10/08 04:22:44]

nit, I think the right syntax is: /*is_data_usage_off_the_record=*/true
(at least I have been told so :P)

See this:
https://code.google.com/p/chromium/codesearch#search/&q=f:src/net%20=%5C*%5C/...

[sclittle, 2015/10/08 19:44:13]

It looks like both styles are used, most of the cases I found are using the
"value /* arg_name */" format though:
https://code.google.com/p/chromium/codesearch#search/&q=lang:c%2B%2B%20%22/*%...

So I'll leave this as-is.

 
   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
   // is fixed.