Record UMA for total data usage consumed by Chromium

components/data_use_measurement/content/data_use_measurement.cc

Index: components/data_use_measurement/content/data_use_measurement.cc
diff --git a/components/data_use_measurement/content/data_use_measurement.cc b/components/data_use_measurement/content/data_use_measurement.cc
index dd70ad5607af5aa785fc97068c66054f5eb9af94..40969da9d9087ee30d096a9261d2e61cf8bc1662 100644
--- a/components/data_use_measurement/content/data_use_measurement.cc
+++ b/components/data_use_measurement/content/data_use_measurement.cc
@@ -14,6 +14,10 @@
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_request.h"
 
+#if defined(OS_ANDROID)
+#include "net/android/traffic_stats.h"
+#endif
+
 namespace data_use_measurement {
 
 namespace {
@@ -52,7 +56,9 @@ DataUseMeasurement::DataUseMeasurement(
       app_state_(base::android::APPLICATION_STATE_HAS_RUNNING_ACTIVITIES),
       app_listener_(new base::android::ApplicationStatusListener(
           base::Bind(&DataUseMeasurement::OnApplicationStateChange,
-                     base::Unretained(this))))
+                     base::Unretained(this)))),
+      rx_bytes_os_(0),
+      tx_bytes_os_(0)
 #endif
 {
 }
@@ -65,6 +71,18 @@ void DataUseMeasurement::OnBeforeRedirect(const net::URLRequest& request,
   ReportDataUseUMA(request);
 }
 
+void DataUseMeasurement::OnNetworkBytesReceived(const net::URLRequest& request,
+                                                int64_t bytes_received) {
+  UMA_HISTOGRAM_COUNTS("DataUse.BytesReceived.Delegate", bytes_received);
+  RecordNetworkBytesReceivedOS();

[sclittle, 2016/09/14 21:28:13]

Is it OK for performance to call this so often? Note that OnNetworkBytesReceived
is called whenever a chunk of a response is received, so e.g. if a large
resource is being downloaded, OnNetworkBytesReceived could be called a bunch of
times.

[tbansal1, 2016/09/15 17:46:04]

Good catch. Fixed.

+}
+
+void DataUseMeasurement::OnNetworkBytesSent(const net::URLRequest& request,
+                                            int64_t bytes_sent) {
+  UMA_HISTOGRAM_COUNTS("DataUse.BytesSent.Delegate", bytes_sent);
+  RecordNetworkBytesSentOS();
+}
+
 void DataUseMeasurement::OnCompleted(const net::URLRequest& request,
                                      bool started) {
   // TODO(amohammadkhan): Verify that there is no double recording in data use
@@ -181,4 +199,30 @@ void DataUseMeasurement::ReportDataUsageServices(
   }
 }
 
+void DataUseMeasurement::RecordNetworkBytesReceivedOS() {

[sclittle, 2016/09/14 21:28:13]

Is there a timing issue here? E.g., suppose there's a whole bunch of data use
that happens at around the same time. Chrome would call into traffic stats
multiple times as it processes the received bytes, but traffic stats would
return the same value for each of these times. So all of those bytes would be
attributed to one of the chunks of Chrome bytes. Is this a problem?

[tbansal1, 2016/09/15 17:46:04]

No, because I am not attributing traffic stats bytes to Chrome bytes. They are
recorded in completely separate histograms.

+#if defined(OS_ANDROID)
+  int64_t bytes = 0;
+  if (net::android::traffic_stats::GetCurrentUidRxBytes(&bytes)) {
+    if (rx_bytes_os_ != 0) {
+      DCHECK_GE(bytes, rx_bytes_os_);

[sclittle, 2016/09/14 21:28:13]

Are you sure you want to crash if this condition doesn't hold?

[tbansal1, 2016/09/15 17:46:04]

Yes, android provides guarantee that this is always increasing.
https://developer.android.com/reference/android/net/TrafficStats.html#getTota...

So, it shouldn't trip on DCHECK.

+      UMA_HISTOGRAM_COUNTS("DataUse.BytesReceived.OS", bytes - rx_bytes_os_);
+    }
+    rx_bytes_os_ = bytes;
+  }
+#endif
+}
+
+void DataUseMeasurement::RecordNetworkBytesSentOS() {
+#if defined(OS_ANDROID)
+  int64_t bytes = 0;
+  if (net::android::traffic_stats::GetCurrentUidTxBytes(&bytes)) {
+    if (tx_bytes_os_ != 0) {
+      DCHECK_GE(bytes, tx_bytes_os_);
+      UMA_HISTOGRAM_COUNTS("DataUse.BytesSent.OS", bytes - tx_bytes_os_);
+    }
+    tx_bytes_os_ = bytes;
+  }
+#endif
+}
+
 }  // namespace data_use_measurement