Bug 1176112 - A/B test for default browser setting UI on Windows 10. r=Gijs

browser/app/profile/firefox.js

@@ -271,6 +271,7 @@ pref("general.autoScroll", true);
 pref("browser.shell.checkDefaultBrowser", true);
 pref("browser.shell.shortcutFavicons",true);
 pref("browser.shell.mostRecentDateSetAsDefault", "");
+pref("browser.shell.windows10DefaultBrowserABTest", -1);
 
 // 0 = blank, 1 = home (browser.startup.homepage), 2 = last visited page, 3 = resume previous browser session
 // The behavior of option 3 is detailed at: http://wiki.mozilla.org/Session_Restore

browser/components/nsBrowserGlue.js

@@ -166,6 +166,9 @@ XPCOMUtils.defineLazyModuleGetter(this, "AddonWatcher",
 XPCOMUtils.defineLazyModuleGetter(this, "LightweightThemeManager",
                                   "resource://gre/modules/LightweightThemeManager.jsm");
 
+XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
+                                  "resource://gre/modules/AppConstants.jsm");
+
 const PREF_PLUGINS_NOTIFYUSER = "plugins.update.notifyUser";
 const PREF_PLUGINS_UPDATEURL  = "plugins.update.url";
 
@@ -1125,6 +1128,17 @@ BrowserGlue.prototype = {
         Services.prefs.setCharPref("browser.shell.mostRecentDateSetAsDefault", now);
       }
 
+      if (Services.prefs.getIntPref("browser.shell.windows10DefaultBrowserABTest") == -1) {
+        let abTest = Math.round(Math.random());
+        Services.prefs.setIntPref("browser.shell.windows10DefaultBrowserABTest", abTest);
+      }
+
+      if (AppConstants.isPlatformAndVersionAtLeast("win", "10")) {
+        let abTest = Services.prefs.getIntPref("browser.shell.windows10DefaultBrowserABTest");
+        let result = abTest * 2 + Number(isDefault);
+        Services.telemetry.getHistogramById("WIN_10_DEFAULT_BROWSER_AB_TEST").add(result);
+      }
+
       if (shouldCheck && !isDefault && !willRecoverSession) {
         Services.tm.mainThread.dispatch(function() {
           DefaultBrowserCheck.prompt(RecentWindow.getMostRecentBrowserWindow());

browser/components/shell/nsWindowsShellService.cpp

@@ -744,6 +744,7 @@ nsWindowsShellService::SetDefaultBrowser(bool aClaimAllTypes, bool aForAllUsers)
   }
 
   nsresult rv = LaunchHelper(appHelperPath);
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
   if (NS_SUCCEEDED(rv) && IsWin8OrLater()) {
     if (aClaimAllTypes) {
       if (IsWin10OrLater()) {
@@ -761,11 +762,18 @@ nsWindowsShellService::SetDefaultBrowser(bool aClaimAllTypes, bool aForAllUsers)
         }
       }
     } else {
-      // Windows 10 blocks attempts to load the HTTP Handler
+      // Windows 10 blocks attempts to load the
-      // association dialog, so the modern Settings dialog
+      // HTTP Handler association dialog.
-      // is opened with the Default Apps view loaded.
       if (IsWin10OrLater()) {
+        if (prefs) {
+          int32_t abTest;
+          rv = prefs->GetIntPref("browser.shell.windows10DefaultBrowserABTest", &abTest);
+          if (NS_SUCCEEDED(rv) && abTest == 0) {
             rv = InvokeHTTPOpenAsVerb();
+          } else {
+            rv = LaunchModernSettingsDialogDefaultApps();
+          }
+        }
       } else {
         rv = LaunchHTTPHandlerPane();
       }
@@ -782,7 +790,6 @@ nsWindowsShellService::SetDefaultBrowser(bool aClaimAllTypes, bool aForAllUsers)
     }
   }
 
-  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
   if (prefs) {
     (void) prefs->SetBoolPref(PREF_CHECKDEFAULTBROWSER, true);
   }

toolkit/components/telemetry/Histograms.json

@@ -6880,6 +6880,13 @@
     "kind": "boolean",
     "description": "The result of the startup default desktop browser check."
   },
+  "WIN_10_DEFAULT_BROWSER_AB_TEST": {
+    "alert_emails": ["jwein@mozilla.com"],
+    "expires_in_version": "45",
+    "kind": "enumerated",
+    "n_values": 4,
+    "description": "A/B test of different default browser dialogs on Windows 10 (0=openas-notdefault, 1=openas-default, 2=modernsettings-notdefault, 3=modernsettings-default)."
+  },
   "BROWSER_IS_ASSIST_DEFAULT": {
     "expires_in_version": "never",
     "kind": "boolean",

toolkit/modules/AppConstants.jsm

@@ -5,6 +5,9 @@
 
 "use strict";
 
+Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Services", "resource://gre/modules/Services.jsm");
+
 this.EXPORTED_SYMBOLS = ["AppConstants"];
 
 // Immutable for export.
@@ -130,6 +133,12 @@ this.AppConstants = Object.freeze({
   "other",
 #endif
 
+  isPlatformAndVersionAtLeast(platform, version) {
+    let platformVersion = Services.sysinfo.getProperty("version");
+    return platform == this.platform &&
+           Services.vc.compare(platformVersion, version) >= 0;
+  },
+
   MOZ_CRASHREPORTER:
 #ifdef MOZ_CRASHREPORTER
   true,