Bug 1410101 - Replace "Preferences::GetBool("toolkit.telemetry.enabled")" with "Telemetry::CanRecordPrereleaseData()" in BackgroundHangMonitor.cpp to determine if it needs to be enabled or not. r=chutten

Indicates whether Telemetry pre-release data recording is turned on. Tends to be true on pre-release channels. Also, this attribute is read-only. @see nsITelemetry.canRecordPrereleaseData.

--HG--
extra : rebase_source : a437a62ea427ada3bd3b6e63beec2033b2500e9b

toolkit/components/backgroundhangmonitor/BackgroundHangMonitor.cpp

@@ -577,7 +577,7 @@ BackgroundHangMonitor::DisableOnBeta() {
   nsAutoCString clientID;
   nsresult rv =
     Preferences::GetCString("toolkit.telemetry.cachedClientID", clientID);
-  bool telemetryEnabled = Preferences::GetBool("toolkit.telemetry.enabled");
+  bool telemetryEnabled = Telemetry::CanRecordPrereleaseData();
 
   if (!telemetryEnabled || NS_FAILED(rv) ||
       BackgroundHangMonitor::ShouldDisableOnBeta(clientID)) {