Bug 695829 - Add telemetry metrics for private browsing transitions. r=ehsan

--HG--
rename : browser/components/privatebrowsing/test/unit/test_privatebrowsing_autostart.js => browser/components/privatebrowsing/test/unit/test_privatebrowsing_telemetry.js
rename : browser/components/privatebrowsing/test/unit/test_privatebrowsingwrapper_autostart.js => browser/components/privatebrowsing/test/unit/test_privatebrowsingwrapper_telemetry.js

browser/components/privatebrowsing/src/nsPrivateBrowsingService.js

@@ -133,6 +133,10 @@ PrivateBrowsingService.prototype = {
   // Whether private browsing has been turned on from the command line
   _lastChangedByCommandLine: false,
 
+  // Telemetry measurements
+  _enterTimestamps: {},
+  _exitTimestamps: {},
+
   // XPCOM registration
   classID: Components.ID("{c31f4883-839b-45f6-82ad-a6a9bc5ad599}"),
 
@@ -308,6 +312,7 @@ PrivateBrowsingService.prototype = {
         // restore has been completed
         this._currentStatus = STATE_IDLE;
         this._obs.notifyObservers(null, "private-browsing-transition-complete", "");
+        this._recordTransitionTime("completed");
         break;
       case STATE_WAITING_FOR_RESTORE:
         // too soon to notify...
@@ -323,6 +328,51 @@ PrivateBrowsingService.prototype = {
     }
   },
 
+  _recordTransitionTime: function PBS__recordTransitionTime(aPhase) {
+    // To record the time spent in private browsing transitions, note that we
+    // cannot use the TelemetryStopwatch module, because it reports its results
+    // immediately when the timer is stopped.  In this case, we need to delay
+    // the actual histogram update after we are out of private browsing mode.
+    if (this._inPrivateBrowsing) {
+      this._enterTimestamps[aPhase] = Date.now();
+    } else {
+      if (this._quitting) {
+        // If we are quitting the browser, we don't care collecting the data,
+        // because we wouldn't be able to record it with telemetry.
+        return;
+      }
+      this._exitTimestamps[aPhase] = Date.now();
+      if (aPhase == "completed") {
+        // After we finished exiting the private browsing mode, we can finally
+        // record the telemetry data, for the enter and the exit processes.
+        this._reportTelemetry();
+      }
+    }
+  },
+
+  _reportTelemetry: function PBS__reportTelemetry() {
+    function reportTelemetryEntry(aHistogramId, aValue) {
+      try {
+        Services.telemetry.getHistogramById(aHistogramId).add(aValue);
+      } catch (ex) {
+        Cu.reportError(ex);
+      }
+    }
+
+    reportTelemetryEntry(
+          "PRIVATE_BROWSING_TRANSITION_ENTER_PREPARATION_MS",
+          this._enterTimestamps.prepared - this._enterTimestamps.started);
+    reportTelemetryEntry(
+          "PRIVATE_BROWSING_TRANSITION_ENTER_TOTAL_MS",
+          this._enterTimestamps.completed - this._enterTimestamps.started);
+    reportTelemetryEntry(
+          "PRIVATE_BROWSING_TRANSITION_EXIT_PREPARATION_MS",
+          this._exitTimestamps.prepared - this._exitTimestamps.started);
+    reportTelemetryEntry(
+          "PRIVATE_BROWSING_TRANSITION_EXIT_TOTAL_MS",
+          this._exitTimestamps.completed - this._exitTimestamps.started);
+  },
+
   _canEnterPrivateBrowsingMode: function PBS__canEnterPrivateBrowsingMode() {
     let cancelEnter = Cc["@mozilla.org/supports-PRBool;1"].
                       createInstance(Ci.nsISupportsPRBool);
@@ -537,6 +587,8 @@ PrivateBrowsingService.prototype = {
       this._autoStarted = this._prefs.getBoolPref("browser.privatebrowsing.autostart");
       this._inPrivateBrowsing = val != false;
 
+      this._recordTransitionTime("started");
+
       let data = val ? "enter" : "exit";
 
       let quitting = Cc["@mozilla.org/supports-PRBool;1"].
@@ -551,6 +603,8 @@ PrivateBrowsingService.prototype = {
 
       this._obs.notifyObservers(quitting, "private-browsing", data);
 
+      this._recordTransitionTime("prepared");
+
       // load the appropriate session
       this._onAfterPrivateBrowsingModeChange();
     } catch (ex) {

browser/components/privatebrowsing/test/unit/do_test_privatebrowsing_telemetry.js

@@ -0,0 +1,42 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyServiceGetter(this, "gPrivateBrowsing",
+                                   PRIVATEBROWSING_CONTRACT_ID,
+                                   "nsIPrivateBrowsingService");
+
+function waitForTransition(aEnabled, aCallback) {
+  Services.obs.addObserver(function PBT_transition(aSubject, aTopic, aData) {
+    Services.obs.removeObserver(PBT_transition, aTopic, false);
+    // Telemetry data is recorded just after the private browsing transition
+    // observers are notified, thus we must wait for this observer to return.
+    do_execute_soon(aCallback);
+  }, "private-browsing-transition-complete", false);
+  gPrivateBrowsing.privateBrowsingEnabled = aEnabled;
+}
+
+function checkHistogram(aId) {
+  // Check that we have data either in the first bucket (that doesn't
+  // count towards the sum) or one of the other buckets, by checking
+  // the sum of the values.
+  let snapshot = Services.telemetry.getHistogramById(aId).snapshot();
+  do_check_true(snapshot.sum > 0 || snapshot.counts[0] > 0);
+}
+
+function do_test() {
+  do_test_pending();
+
+  waitForTransition(true, function PBT_enabled() {
+    waitForTransition(false, function PBT_disabled() {
+      checkHistogram("PRIVATE_BROWSING_TRANSITION_ENTER_PREPARATION_MS");
+      checkHistogram("PRIVATE_BROWSING_TRANSITION_ENTER_TOTAL_MS");
+      checkHistogram("PRIVATE_BROWSING_TRANSITION_EXIT_PREPARATION_MS");
+      checkHistogram("PRIVATE_BROWSING_TRANSITION_EXIT_TOTAL_MS");
+
+      do_test_finished();
+    });
+  });
+}

browser/components/privatebrowsing/test/unit/test_privatebrowsing_telemetry.js

@@ -0,0 +1,44 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Private Browsing Tests.
+ *
+ * The Initial Developer of the Original Code is
+ * Ehsan Akhgari.
+ * Portions created by the Initial Developer are Copyright (C) 2008
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Ehsan Akhgari <ehsan.akhgari@gmail.com> (Original Author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+// Checks that telemetry data for private browsing transitions is recorded.
+
+function run_test() {
+  PRIVATEBROWSING_CONTRACT_ID = "@mozilla.org/privatebrowsing;1";
+  load("do_test_privatebrowsing_telemetry.js");
+  do_test();
+}

browser/components/privatebrowsing/test/unit/test_privatebrowsingwrapper_telemetry.js

@@ -0,0 +1,44 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Private Browsing Tests.
+ *
+ * The Initial Developer of the Original Code is
+ * Ehsan Akhgari.
+ * Portions created by the Initial Developer are Copyright (C) 2009
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Ehsan Akhgari <ehsan.akhgari@gmail.com> (Original Author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+// Checks that telemetry data for private browsing transitions is recorded.
+
+function run_test() {
+  PRIVATEBROWSING_CONTRACT_ID = "@mozilla.org/privatebrowsing-wrapper;1";
+  load("do_test_privatebrowsing_telemetry.js");
+  do_test();
+}

browser/components/privatebrowsing/test/unit/xpcshell.ini

@@ -12,12 +12,14 @@ tail = tail_privatebrowsing.js
 [test_privatebrowsing_autostart.js]
 [test_privatebrowsing_commandline.js]
 [test_privatebrowsing_exit.js]
+[test_privatebrowsing_telemetry.js]
 [test_privatebrowsingwrapper_autostart.js]
 [test_privatebrowsingwrapper_commandline.js]
 [test_privatebrowsingwrapper_exit.js]
 [test_privatebrowsingwrapper_placesTitleNoUpdate.js]
 [test_privatebrowsingwrapper_removeDataFromDomain.js]
 [test_privatebrowsingwrapper_removeDataFromDomain_activeDownloads.js]
+[test_privatebrowsingwrapper_telemetry.js]
 [test_removeDataFromDomain.js]
 [test_removeDataFromDomain_activeDownloads.js]
 [test_transition_nooffline.js]

toolkit/components/telemetry/TelemetryHistograms.h

@@ -395,6 +395,14 @@ HISTOGRAM(XUL_INITIAL_FRAME_CONSTRUCTION, 1, 3000, 10, EXPONENTIAL, "initial xul
 HISTOGRAM_BOOLEAN(XMLHTTPREQUEST_ASYNC_OR_SYNC, "Type of XMLHttpRequest, async or sync")
 HISTOGRAM_BOOLEAN(MULTIPART_XHR_RESPONSE, "XMLHttpRequest response was of type multipart/x-mixed-replace.")
 
+/**
+ * Private browsing transition telemetry.
+ */
+HISTOGRAM(PRIVATE_BROWSING_TRANSITION_ENTER_PREPARATION_MS, 1, 3000, 10, EXPONENTIAL, "Time spent on private browsing enter transition, excluding session restore (ms)")
+HISTOGRAM(PRIVATE_BROWSING_TRANSITION_ENTER_TOTAL_MS, 1, 10000, 50, EXPONENTIAL, "Time spent on private browsing enter transition, including session restore (ms)")
+HISTOGRAM(PRIVATE_BROWSING_TRANSITION_EXIT_PREPARATION_MS, 1, 3000, 10, EXPONENTIAL, "Time spent on private browsing exit transition, excluding session restore (ms)")
+HISTOGRAM(PRIVATE_BROWSING_TRANSITION_EXIT_TOTAL_MS, 1, 10000, 50, EXPONENTIAL, "Time spent on private browsing exit transition, including session restore (ms)")
+
 /**
  * DOM telemetry.
  */