Bug 1473631: Part 15 - Use a single pref observer for all telemetry environment preferences. r=gfritzsche

MozReview-Commit-ID: dGJDjUP4Vm

--HG--
extra : rebase_source : d7e801b2d5b3b0e1b390a78c835e445eda1d9ac6
extra : amend_source : 342b24fec8ee3cea9677080f588593405b233734

toolkit/components/telemetry/TelemetryEnvironment.jsm

@@ -1124,11 +1124,7 @@ EnvironmentCache.prototype = {
   _startWatchingPrefs() {
     this._log.trace("_startWatchingPrefs - " + this._watchedPrefs);
 
-    for (let [pref, options] of this._watchedPrefs) {
-      if (!("requiresRestart" in options) || !options.requiresRestart) {
-        Services.prefs.addObserver(pref, this, true);
-      }
-    }
+    Services.prefs.addObserver("", this, true);
   },
 
   _onPrefChanged(aData) {
@@ -1144,11 +1140,7 @@ EnvironmentCache.prototype = {
   _stopWatchingPrefs() {
     this._log.trace("_stopWatchingPrefs");
 
-    for (let [pref, options] of this._watchedPrefs) {
-      if (!("requiresRestart" in options) || !options.requiresRestart) {
-        Services.prefs.removeObserver(pref, this);
-      }
-    }
+    Services.prefs.removeObserver("", this);
   },
 
   _addObservers() {
@@ -1220,7 +1212,8 @@ EnvironmentCache.prototype = {
         this._updateDefaultBrowser();
         break;
       case PREF_CHANGED_TOPIC:
-        if (this._watchedPrefs.has(aData)) {
+        let options = this._watchedPrefs.get(aData);
+        if (options && !options.requiresRestart) {
           this._onPrefChanged(aData);
         }
         break;