Issue mcp-graveyard/UXP#991 Part 7: Toolkit Components

18 files changed, 55 insertions, 204 deletions

diff --git a/toolkit/components/asyncshutdown/AsyncShutdown.jsm b/toolkit/components/asyncshutdown/AsyncShutdown.jsm
index 62ac36f42c..9cdf9e126d 100644
--- a/toolkit/components/asyncshutdown/AsyncShutdown.jsm
+++ b/toolkit/components/asyncshutdown/AsyncShutdown.jsm
@@ -79,12 +79,8 @@ const DELAY_WARNING_MS = 10 * 1000;
 // Crash the process if shutdown is really too long
 // (allowing for sleep).
 const PREF_DELAY_CRASH_MS = "toolkit.asyncshutdown.crash_timeout";
-var DELAY_CRASH_MS = 60 * 1000; // One minute
-try {
-  DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS);
-} catch (ex) {
-  // Ignore errors
-}
+var DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS,
+                                               60 * 1000); // One minute
 Services.prefs.addObserver(PREF_DELAY_CRASH_MS, function() {
   DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS);
 }, false);
@@ -207,12 +203,7 @@ function log(msg, prefix = "", error = null) {
   }
 }
 const PREF_DEBUG_LOG = "toolkit.asyncshutdown.log";
-var DEBUG_LOG = false;
-try {
-  DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG);
-} catch (ex) {
-  // Ignore errors
-}
+var DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG, false);
 Services.prefs.addObserver(PREF_DEBUG_LOG, function() {
   DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG);
 }, false);
@@ -360,12 +351,7 @@ this.AsyncShutdown = {
    * Access function getPhase. For testing purposes only.
    */
   get _getPhase() {
-    let accepted = false;
-    try {
-      accepted = Services.prefs.getBoolPref("toolkit.asyncshutdown.testing");
-    } catch (ex) {
-      // Ignore errors
-    }
+    let accepted = Services.prefs.getBoolPref("toolkit.asyncshutdown.testing", false);
     if (accepted) {
       return getPhase;
     }
@@ -464,12 +450,7 @@ function getPhase(topic) {
      * notification. For testing purposes only.
      */
     get _trigger() {
-      let accepted = false;
-      try {
-        accepted = Services.prefs.getBoolPref("toolkit.asyncshutdown.testing");
-      } catch (ex) {
-        // Ignore errors
-      }
+      let accepted = Services.prefs.getBoolPref("toolkit.asyncshutdown.testing", false);
       if (accepted) {
         return () => spinner.observe();
       }
diff --git a/toolkit/components/blocklist/nsBlocklistService.js b/toolkit/components/blocklist/nsBlocklistService.js
index 49033fc8f6..b0115e25d8 100644
--- a/toolkit/components/blocklist/nsBlocklistService.js
+++ b/toolkit/components/blocklist/nsBlocklistService.js
@@ -238,16 +238,7 @@ function getLocale() {
 
 /* Get the distribution pref values, from defaults only */
 function getDistributionPrefValue(aPrefName) {
-  var prefValue = "default";
-
-  var defaults = gPref.getDefaultBranch(null);
-  try {
-    prefValue = defaults.getCharPref(aPrefName);
-  } catch (e) {
-    // use default when pref not found
-  }
-
-  return prefValue;
+  return gPref.getDefaultBranch(null).getCharPref(aPrefName, "default");
 }
 
 /**
diff --git a/toolkit/components/jsdownloads/src/DownloadIntegration.jsm b/toolkit/components/jsdownloads/src/DownloadIntegration.jsm
index 3052847497..a6875ec48f 100644
--- a/toolkit/components/jsdownloads/src/DownloadIntegration.jsm
+++ b/toolkit/components/jsdownloads/src/DownloadIntegration.jsm
@@ -368,11 +368,7 @@ this.DownloadIntegration = {
    */
   getPreferredDownloadsDirectory: Task.async(function* () {
     let directoryPath = null;
-    let prefValue = 1;
-
-    try {
-      prefValue = Services.prefs.getIntPref("browser.download.folderList");
-    } catch(e) {}
+    let prefValue = Services.prefs.getIntPref("browser.download.folderList", 1);
 
     switch(prefValue) {
       case 0: // Desktop
diff --git a/toolkit/components/nsDefaultCLH.js b/toolkit/components/nsDefaultCLH.js
index a081bae498..affbf75ee4 100644
--- a/toolkit/components/nsDefaultCLH.js
+++ b/toolkit/components/nsDefaultCLH.js
@@ -104,13 +104,7 @@ nsDefaultCLH.prototype = {
     // if the pref is missing, ignore the exception
     try {
       var chromeURI = prefs.getCharPref("toolkit.defaultChromeURI");
-
-      var flags = "chrome,dialog=no,all";
-      try {
-        flags = prefs.getCharPref("toolkit.defaultChromeFeatures");
-      }
-      catch (e) { }
-
+      var flags = prefs.getCharPref("toolkit.defaultChromeFeatures", "chrome,dialog=no,all");
       var wwatch = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                             .getService(nsIWindowWatcher);
       wwatch.openWindow(null, chromeURI, "_blank",
diff --git a/toolkit/components/osfile/modules/osfile_async_front.jsm b/toolkit/components/osfile/modules/osfile_async_front.jsm
index 93c7e66d6c..1d1d7c73fd 100644
--- a/toolkit/components/osfile/modules/osfile_async_front.jsm
+++ b/toolkit/components/osfile/modules/osfile_async_front.jsm
@@ -239,10 +239,9 @@ var Scheduler = this.Scheduler = {
    * Prepare to kill the OS.File worker after a few seconds.
    */
   restartTimer: function(arg) {
-    let delay;
-    try {
-      delay = Services.prefs.getIntPref("osfile.reset_worker_delay");
-    } catch(e) {
+    let delay = Services.prefs.getIntPref("osfile.reset_worker_delay", 0);
+
+    if (!delay) {
       // Don't auto-shutdown if we don't have a delay preference set.
       return;
     }
@@ -469,42 +468,24 @@ const PREF_OSFILE_LOG = "toolkit.osfile.log";
 const PREF_OSFILE_LOG_REDIRECT = "toolkit.osfile.log.redirect";
 
 /**
- * Safely read a PREF_OSFILE_LOG preference.
- * Returns a value read or, in case of an error, oldPref or false.
- *
- * @param bool oldPref
- *        An optional value that the DEBUG flag was set to previously.
- */
-function readDebugPref(prefName, oldPref = false) {
-  let pref = oldPref;
-  try {
-    pref = Services.prefs.getBoolPref(prefName);
-  } catch (x) {
-    // In case of an error when reading a pref keep it as is.
-  }
-  // If neither pref nor oldPref were set, default it to false.
-  return pref;
-};
-
-/**
  * Listen to PREF_OSFILE_LOG changes and update gShouldLog flag
  * appropriately.
  */
 Services.prefs.addObserver(PREF_OSFILE_LOG,
   function prefObserver(aSubject, aTopic, aData) {
-    SharedAll.Config.DEBUG = readDebugPref(PREF_OSFILE_LOG, SharedAll.Config.DEBUG);
+    SharedAll.Config.DEBUG = Services.prefs.getBoolPref(PREF_OSFILE_LOG, SharedAll.Config.DEBUG);
     if (Scheduler.launched) {
       // Don't start the worker just to set this preference.
       Scheduler.post("SET_DEBUG", [SharedAll.Config.DEBUG]);
     }
   }, false);
-SharedAll.Config.DEBUG = readDebugPref(PREF_OSFILE_LOG, false);
+SharedAll.Config.DEBUG = Services.prefs.getBoolPref(PREF_OSFILE_LOG, false);
 
 Services.prefs.addObserver(PREF_OSFILE_LOG_REDIRECT,
   function prefObserver(aSubject, aTopic, aData) {
-    SharedAll.Config.TEST = readDebugPref(PREF_OSFILE_LOG_REDIRECT, OS.Shared.TEST);
+    SharedAll.Config.TEST = Services.prefs.getBoolPref(PREF_OSFILE_LOG_REDIRECT, OS.Shared.TEST);
   }, false);
-SharedAll.Config.TEST = readDebugPref(PREF_OSFILE_LOG_REDIRECT, false);
+SharedAll.Config.TEST = Services.prefs.getBoolPref(PREF_OSFILE_LOG_REDIRECT, false);
 
 
 /**
@@ -515,7 +496,7 @@ var nativeWheneverAvailable = true;
 const PREF_OSFILE_NATIVE = "toolkit.osfile.native";
 Services.prefs.addObserver(PREF_OSFILE_NATIVE,
   function prefObserver(aSubject, aTopic, aData) {
-    nativeWheneverAvailable = readDebugPref(PREF_OSFILE_NATIVE, nativeWheneverAvailable);
+    nativeWheneverAvailable = Services.prefs.getBoolPref(PREF_OSFILE_NATIVE, nativeWheneverAvailable);
   }, false);
 
 
@@ -557,10 +538,9 @@ Services.prefs.addObserver(PREF_OSFILE_TEST_SHUTDOWN_OBSERVER,
   function prefObserver() {
     // The temporary phase topic used to trigger the unclosed
     // phase warning.
-    let TOPIC = null;
+    let TOPIC = Services.prefs.getCharPref(PREF_OSFILE_TEST_SHUTDOWN_OBSERVER,
+                                           "");
     try {
-      TOPIC = Services.prefs.getCharPref(
-        PREF_OSFILE_TEST_SHUTDOWN_OBSERVER);
     } catch (x) {
     }
     if (TOPIC) {
diff --git a/toolkit/components/places/PlacesCategoriesStarter.js b/toolkit/components/places/PlacesCategoriesStarter.js
index 560bd486a8..bab14db52d 100644
--- a/toolkit/components/places/PlacesCategoriesStarter.js
+++ b/toolkit/components/places/PlacesCategoriesStarter.js
@@ -77,11 +77,8 @@ PlacesCategoriesStarter.prototype = {
         break;
       case "idle-daily":
         // Once a week run places.sqlite maintenance tasks.
-        let lastMaintenance = 0;
-        try {
-          lastMaintenance =
-            Services.prefs.getIntPref("places.database.lastMaintenance");
-        } catch (ex) {}
+        let lastMaintenance =
+            Services.prefs.getIntPref("places.database.lastMaintenance", 0);
         let nowSeconds = parseInt(Date.now() / 1000);
         if (lastMaintenance < nowSeconds - MAINTENANCE_INTERVAL_SECONDS) {
           PlacesDBUtils.maintenanceOnIdle();
diff --git a/toolkit/components/places/PlacesRemoteTabsAutocompleteProvider.jsm b/toolkit/components/places/PlacesRemoteTabsAutocompleteProvider.jsm
index d23d5bc6e7..c3bc501eb2 100644
--- a/toolkit/components/places/PlacesRemoteTabsAutocompleteProvider.jsm
+++ b/toolkit/components/places/PlacesRemoteTabsAutocompleteProvider.jsm
@@ -95,11 +95,7 @@ function observe(subject, topic, data) {
 
     case "nsPref:changed":
       if (data == PREF_SHOW_REMOTE_ICONS) {
-        try {
-          showRemoteIcons = Services.prefs.getBoolPref(PREF_SHOW_REMOTE_ICONS);
-        } catch (_) {
-          showRemoteIcons = true; // no such pref - default is to show the icons.
-        }
+        showRemoteIcons = Services.prefs.getBoolPref(PREF_SHOW_REMOTE_ICONS, true);
       }
       break;
 
diff --git a/toolkit/components/places/UnifiedComplete.js b/toolkit/components/places/UnifiedComplete.js
index ec5f911115..7b63e29bb4 100644
--- a/toolkit/components/places/UnifiedComplete.js
+++ b/toolkit/components/places/UnifiedComplete.js
@@ -437,10 +437,7 @@ XPCOMUtils.defineLazyGetter(this, "Prefs", () => {
     store.suggestTyped = prefs.get(...PREF_SUGGEST_HISTORY_ONLYTYPED);
     store.suggestSearches = prefs.get(...PREF_SUGGEST_SEARCHES);
     store.maxCharsForSearchSuggestions = prefs.get(...PREF_MAX_CHARS_FOR_SUGGEST);
-    store.keywordEnabled = true;
-    try {
-      store.keywordEnabled = Services.prefs.getBoolPref("keyword.enabled");
-    } catch (ex) {}
+    store.keywordEnabled = Services.prefs.getBoolPref("keyword.enabled", true);
 
     // If history is not set, onlyTyped value should be ignored.
     if (!store.suggestHistory) {
diff --git a/toolkit/components/places/nsPlacesExpiration.js b/toolkit/components/places/nsPlacesExpiration.js
index 499934362d..767a4d3458 100644
--- a/toolkit/components/places/nsPlacesExpiration.js
+++ b/toolkit/components/places/nsPlacesExpiration.js
@@ -812,11 +812,8 @@ nsPlacesExpiration.prototype = {
 
   _loadPrefs: Task.async(function* () {
     // Get the user's limit, if it was set.
-    try {
-      // We want to silently fail since getIntPref throws if it does not exist,
-      // and use a default to fallback to.
-      this._urisLimit = this._prefBranch.getIntPref(PREF_MAX_URIS);
-    } catch (ex) { /* User limit not set */ }
+    this._urisLimit = this._prefBranch.getIntPref(PREF_MAX_URIS,
+                                                  PREF_MAX_URIS_NOTSET);
 
     if (this._urisLimit < 0) {
       // Some testing code expects a pref change to be synchronous, so
@@ -874,11 +871,8 @@ nsPlacesExpiration.prototype = {
                                 this._urisLimit);
 
     // Get the expiration interval value.
-    try {
-      // We want to silently fail since getIntPref throws if it does not exist,
-      // and use a default to fallback to.
-      this._interval = this._prefBranch.getIntPref(PREF_INTERVAL_SECONDS);
-    } catch (ex) { /* User interval not set */ }
+    this._interval = this._prefBranch.getIntPref(PREF_INTERVAL_SECONDS,
+                                                 PREF_INTERVAL_SECONDS_NOTSET);
     if (this._interval <= 0) {
       this._interval = PREF_INTERVAL_SECONDS_NOTSET;
     }
diff --git a/toolkit/components/places/tests/unit/test_000_frecency.js b/toolkit/components/places/tests/unit/test_000_frecency.js
index 0a7347a026..64ee86b593 100644
--- a/toolkit/components/places/tests/unit/test_000_frecency.js
+++ b/toolkit/components/places/tests/unit/test_000_frecency.js
@@ -56,14 +56,8 @@ var prefPrefix = "places.frecency.";
 function* task_initializeBucket(bucket) {
   let [cutoffName, weightName] = bucket;
   // get pref values
-  var weight = 0, cutoff = 0;
-  try {
-    weight = prefs.getIntPref(prefPrefix + weightName);
-  } catch (ex) {}
-  try {
-    cutoff = prefs.getIntPref(prefPrefix + cutoffName);
-  } catch (ex) {}
-
+  var weight = prefs.getIntPref(prefPrefix + weightName, 0);
+  var cutoff = prefs.getIntPref(prefPrefix + cutoffName, 0);
   if (cutoff < 1)
     return;
 
diff --git a/toolkit/components/printing/content/printPageSetup.js b/toolkit/components/printing/content/printPageSetup.js
index 31eb1bdd34..6bcd972076 100644
--- a/toolkit/components/printing/content/printPageSetup.js
+++ b/toolkit/components/printing/content/printPageSetup.js
@@ -65,14 +65,7 @@ function initDialog()
 // ---------------------------------------------------
 function isListOfPrinterFeaturesAvailable()
 {
-  var has_printerfeatures = false;
-
-  try {
-    has_printerfeatures = gPrefs.getBoolPref("print.tmp.printerfeatures." + gPrintSettings.printerName + ".has_special_printerfeatures");
-  } catch (ex) {
-  }
-
-  return has_printerfeatures;
+  return gPrefs.getBoolPref("print.tmp.printerfeatures." + gPrintSettings.printerName + ".has_special_printerfeatures", false);
 }
 
 // ---------------------------------------------------
diff --git a/toolkit/components/printing/content/printdialog.js b/toolkit/components/printing/content/printdialog.js
index e5a38ddced..f9ed94badd 100644
--- a/toolkit/components/printing/content/printdialog.js
+++ b/toolkit/components/printing/content/printdialog.js
@@ -79,15 +79,7 @@ function stripTrailingWhitespace(element)
 // ---------------------------------------------------
 function getPrinterDescription(printerName)
 {
-  var s = "";
-
-  try {
-    /* This may not work with non-ASCII test (see bug 235763 comment #16) */
-    s = gPrefs.getCharPref("print.printer_" + printerName + ".printer_description")
-  } catch (e) {
-  }
-
-  return s;
+  return gPrefs.getCharPref("print.printer_" + printerName + ".printer_description", "")
 }
 
 // ---------------------------------------------------
diff --git a/toolkit/components/printing/content/printjoboptions.js b/toolkit/components/printing/content/printjoboptions.js
index 26f3ffd854..098358940e 100644
--- a/toolkit/components/printing/content/printjoboptions.js
+++ b/toolkit/components/printing/content/printjoboptions.js
@@ -33,14 +33,7 @@ function checkDouble(element, maxVal)
 // ---------------------------------------------------
 function isListOfPrinterFeaturesAvailable()
 {
-  var has_printerfeatures = false;
-
-  try {
-    has_printerfeatures = gPrefs.getBoolPref("print.tmp.printerfeatures." + gPrintSettings.printerName + ".has_special_printerfeatures");
-  } catch (ex) {
-  }
-
-  return has_printerfeatures;
+  return gPrefs.getBoolPref("print.tmp.printerfeatures." + gPrintSettings.printerName + ".has_special_printerfeatures", false);
 }
 
 // ---------------------------------------------------
diff --git a/toolkit/components/search/current/nsSearchService.js b/toolkit/components/search/current/nsSearchService.js
index 2a86010780..66866540a7 100644
--- a/toolkit/components/search/current/nsSearchService.js
+++ b/toolkit/components/search/current/nsSearchService.js
@@ -390,12 +390,7 @@ function isPartnerBuild() {
 
 // Method to determine if we should be using geo-specific defaults
 function geoSpecificDefaultsEnabled() {
-  let geoSpecificDefaults = false;
-  try {
-    geoSpecificDefaults = Services.prefs.getBoolPref("browser.search.geoSpecificDefaults");
-  } catch (e) {}
-
-  return geoSpecificDefaults;
+  return Services.prefs.getBoolPref("browser.search.geoSpecificDefaults", false);
 }
 
 // Some notes on countryCode and region prefs:
@@ -500,11 +495,7 @@ function isUSTimezone() {
 // If it fails we don't touch that pref so isUS() does its normal thing.
 var ensureKnownCountryCode = Task.async(function* (ss) {
   // If we have a country-code already stored in our prefs we trust it.
-  let countryCode;
-  try {
-    countryCode = Services.prefs.getCharPref("browser.search.countryCode");
-  } catch (e) {}
-
+  let countryCode = Services.prefs.getCharPref("browser.search.countryCode", "");
   if (!countryCode) {
     // We don't have it cached, so fetch it. fetchCountryCode() will call
     // storeCountryCode if it gets a result (even if that happens after the
@@ -726,10 +717,7 @@ var fetchRegionDefault = (ss) => new Promise(resolve => {
 
   // Append the optional cohort value.
   const cohortPref = "browser.search.cohort";
-  let cohort;
-  try {
-    cohort = Services.prefs.getCharPref(cohortPref);
-  } catch (e) {}
+  let cohort = Services.prefs.getCharPref(cohortPref, "");
   if (cohort)
     endpoint += "/" + cohort;
 
@@ -993,19 +981,13 @@ function QueryParameter(aName, aValue, aPurpose) {
 function ParamSubstitution(aParamValue, aSearchTerms, aEngine) {
   var value = aParamValue;
 
-  var distributionID = Services.appinfo.distributionID;
-  try {
-    distributionID = Services.prefs.getCharPref(BROWSER_SEARCH_PREF + "distributionID");
-  }
-  catch (ex) { }
-  var official = MOZ_OFFICIAL;
-  try {
-    if (Services.prefs.getBoolPref(BROWSER_SEARCH_PREF + "official"))
-      official = "official";
-    else
-      official = "unofficial";
-  }
-  catch (ex) { }
+  var distributionID = Services.prefs.getCharPref(BROWSER_SEARCH_PREF + "distributionID",
+                                                Services.appinfo.distributionID || "");
+  var official;
+  if (Services.prefs.getBoolPref(BROWSER_SEARCH_PREF + "official", MOZ_OFFICIAL))
+    official = "official";
+  else
+    official = "unofficial";
 
   // Custom search parameters. These are only available to default search
   // engines.
diff --git a/toolkit/components/search/orginal/nsSearchService.js b/toolkit/components/search/orginal/nsSearchService.js
index 5b5ce7a577..c4481df5f3 100644
--- a/toolkit/components/search/orginal/nsSearchService.js
+++ b/toolkit/components/search/orginal/nsSearchService.js
@@ -418,12 +418,7 @@ function isPartnerBuild() {
 
 // Method to determine if we should be using geo-specific defaults
 function geoSpecificDefaultsEnabled() {
-  let geoSpecificDefaults = false;
-  try {
-    geoSpecificDefaults = Services.prefs.getBoolPref("browser.search.geoSpecificDefaults");
-  } catch(e) {}
-
-  return geoSpecificDefaults;
+  return Services.prefs.getBoolPref("browser.search.geoSpecificDefaults", false);
 }
 
 // Some notes on countryCode and region prefs:
@@ -528,11 +523,7 @@ function isUSTimezone() {
 // If it fails we don't touch that pref so isUS() does its normal thing.
 var ensureKnownCountryCode = Task.async(function* () {
   // If we have a country-code already stored in our prefs we trust it.
-  let countryCode;
-  try {
-    countryCode = Services.prefs.getCharPref("browser.search.countryCode");
-  } catch(e) {}
-
+  let countryCode = Services.prefs.getCharPref("browser.search.countryCode", "");
   if (!countryCode) {
     // We don't have it cached, so fetch it. fetchCountryCode() will call
     // storeCountryCode if it gets a result (even if that happens after the
@@ -732,10 +723,7 @@ var fetchRegionDefault = () => new Promise(resolve => {
 
   // Append the optional cohort value.
   const cohortPref = "browser.search.cohort";
-  let cohort;
-  try {
-    cohort = Services.prefs.getCharPref(cohortPref);
-  } catch(e) {}
+  let cohort = Services.prefs.getCharPref(cohortPref, "");
   if (cohort)
     endpoint += "/" + cohort;
 
@@ -1034,19 +1022,13 @@ function QueryParameter(aName, aValue, aPurpose) {
 function ParamSubstitution(aParamValue, aSearchTerms, aEngine) {
   var value = aParamValue;
 
-  var distributionID = MOZ_DISTRIBUTION_ID;
-  try {
-    distributionID = Services.prefs.getCharPref(BROWSER_SEARCH_PREF + "distributionID");
-  }
-  catch (ex) { }
-  var official = MOZ_OFFICIAL;
-  try {
-    if (Services.prefs.getBoolPref(BROWSER_SEARCH_PREF + "official"))
-      official = "official";
-    else
-      official = "unofficial";
-  }
-  catch (ex) { }
+  var distributionID = Services.prefs.getCharPref(BROWSER_SEARCH_PREF + "distributionID",
+                                                MOZ_DISTRIBUTION_ID || "");
+  var official;
+  if (Services.prefs.getBoolPref(BROWSER_SEARCH_PREF + "official", MOZ_OFFICIAL))
+    official = "official";
+  else
+    official = "unofficial";
 
   // Custom search parameters. These are only available to default search
   // engines.
diff --git a/toolkit/components/telemetry/UITelemetry.jsm b/toolkit/components/telemetry/UITelemetry.jsm
index bd7a34b725..231b52e23c 100644
--- a/toolkit/components/telemetry/UITelemetry.jsm
+++ b/toolkit/components/telemetry/UITelemetry.jsm
@@ -36,11 +36,7 @@ this.UITelemetry = {
     Services.obs.addObserver(this, "profile-before-change", false);
 
     // Pick up the current value.
-    try {
-      this._enabled = Services.prefs.getBoolPref(PREF_ENABLED);
-    } catch (e) {
-      this._enabled = false;
-    }
+    this._enabled = Services.prefs.getBoolPref(PREF_ENABLED, false);
 
     return this._enabled;
   },
diff --git a/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js b/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
index ba4bf225a6..5d462c90d4 100644
--- a/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
+++ b/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
@@ -20,12 +20,7 @@ Cu.import("resource://gre/modules/NetUtil.jsm");
 
 // Log only if browser.safebrowsing.debug is true
 function log(...stuff) {
-  let logging = null;
-  try {
-    logging = Services.prefs.getBoolPref("browser.safebrowsing.debug");
-  } catch(e) {
-    return;
-  }
+  let logging = Services.prefs.getBoolPref("browser.safebrowsing.debug", false);
   if (!logging) {
     return;
   }
diff --git a/toolkit/components/urlformatter/tests/unit/test_urlformatter.js b/toolkit/components/urlformatter/tests/unit/test_urlformatter.js
index 393b0dc33b..6f218822ae 100644
--- a/toolkit/components/urlformatter/tests/unit/test_urlformatter.js
+++ b/toolkit/components/urlformatter/tests/unit/test_urlformatter.js
@@ -27,11 +27,9 @@ function run_test() {
                 QueryInterface(Ci.nsIXULRuntime);
   var abi = macutils && macutils.isUniversalBinary ? "Universal-gcc3" : appInfo.XPCOMABI;
 
-  let channel = "default";
   let defaults = prefs.QueryInterface(Ci.nsIPrefService).getDefaultBranch(null);
-  try {
-    channel = defaults.getCharPref("app.update.channel");
-  } catch (e) {}
+  let channel = defaults.getCharPref("app.update.channel", "default");
+
   // Set distribution values.
   defaults.setCharPref("distribution.id", "bacon");
   defaults.setCharPref("distribution.version", "1.0");