HistoricNetworkStatsInfoToValue should use statistics prefs values

chrome/test/data/webui/net_internals/bandwidth_view.js

Index: chrome/test/data/webui/net_internals/bandwidth_view.js
diff --git a/chrome/test/data/webui/net_internals/bandwidth_view.js b/chrome/test/data/webui/net_internals/bandwidth_view.js
index 8b9816dac220a6047ec7d5b61f2c93675ea55411..aaaa144d24df424a4cc6946570f470562ff9bfdd 100644
--- a/chrome/test/data/webui/net_internals/bandwidth_view.js
+++ b/chrome/test/data/webui/net_internals/bandwidth_view.js
@@ -59,7 +59,7 @@ BandwidthTask.prototype = {
     assertEquals('string', typeof url);
     this.url_ = url;
     g_browser.addSessionNetworkStatsObserver(this, true);
-    g_browser.addHistoricNetworkStatsObserver(this, false);
+    g_browser.addHistoricNetworkStatsObserver(this, true);
     NetInternalsTest.switchToView('bandwidth');
     chrome.send('loadPage', [this.url_]);
   },
@@ -116,7 +116,7 @@ BandwidthTask.prototype = {
    * @param {object} networkStats State of the network session.
    */
   onSessionNetworkStatsChanged: function(networkStats) {
-    if (this.isDone() || this.sessionVerified)
+    if (this.isDone())
       return;
     // Wait until the received content length is at least the size of
     // our test page and favicon.
@@ -137,15 +137,15 @@ BandwidthTask.prototype = {
    * @param {object} networkStats State of the network session.
    */
   onHistoricNetworkStatsChanged: function(networkStats) {
-    if (this.isDone() || this.historicVerified)
+    if (this.isDone())
       return;
-    // The received content length should be zero since the historic
-    // information only updates every hour.
-    var expectedLength = 0;
-    // Wait until the table has changed, otherwise the columns will be NaN
-    if (!isNaN(this.getBandwidthTableCell_(0, 2))) {
+    // Wait until the received content length is at least the size of
+    // our test page and favicon.
+    var expectedLength = this.expectedLength_ + this.faviconLength_;
+    if (networkStats.historic_received_content_length >= expectedLength) {
       expectLE(expectedLength, networkStats.historic_original_content_length);
-      // Column 2 contains historic information.
+      // Column 2 contains historic information, and it should be the same as
+      // the session information, because previously there was no history.

[mmenke, 2015/03/06 22:20:23]

This assumption isn't necessarily true - remember that we get both of these
asynchronously.  So we get the historic content length at some time from one
thread and we get the session content length at some other time from some other
thread.  It's theoretically possible that the historic information is from a
point in time before the current session information.

[megjablon, 2015/03/06 22:47:59]

I simply reverted this test back to its state before I wrote
DataReductionProxyStatisticsPrefs. We had to stop testing the historic network
stats since they wouldn't update for an hour. I think this is saying that since
we have no previous history, we know that the expected length is the same as
what we have seen in this session. It doesn't test that at this time they are
the same value. I can change the wording to something like

"The expected length should only be what has been collected in this session,
because previously there was no history."

[mmenke, 2015/03/09 16:00:21]

That new text works for me.

[megjablon, 2015/03/09 20:15:40]

Done.

       this.validateBandwidthTableColumn_(2, expectedLength, expectedLength);
       this.historicVerified = true;
       this.completeIfDone();