Bug 1429885 Support a rounding value of 0 for reduceTimerPrecision r=bkelly,timhuang

MozReview-Commit-ID: F96EUfXgK9F

--HG--
extra : rebase_source : a07dc479dc895cd06fb59902d1eacaeaec30266b

toolkit/components/resistfingerprinting/nsRFPService.cpp

@@ -77,6 +77,21 @@ nsRFPService::GetOrCreate()
   return sRFPService;
 }
 
+/* static */
+bool
+nsRFPService::IsResistFingerprintingEnabled()
+{
+  return sPrivacyResistFingerprinting;
+}
+
+/* static */
+bool
+nsRFPService::IsTimerPrecisionReductionEnabled()
+{
+  return (sPrivacyTimerPrecisionReduction || IsResistFingerprintingEnabled()) &&
+         sResolutionUSec != 0;
+}
+
 /* static */
 double
 nsRFPService::ReduceTimePrecisionAsMSecs(double aTime)

toolkit/components/resistfingerprinting/nsRFPService.h

@@ -53,14 +53,8 @@ public:
   NS_DECL_NSIOBSERVER
 
   static nsRFPService* GetOrCreate();
-  static bool IsResistFingerprintingEnabled()
-  {
-    return sPrivacyResistFingerprinting;
-  }
-  static bool IsTimerPrecisionReductionEnabled()
-  {
-    return sPrivacyTimerPrecisionReduction || IsResistFingerprintingEnabled();
-  }
+  static bool IsResistFingerprintingEnabled();
+  static bool IsTimerPrecisionReductionEnabled();
 
   // The following Reduce methods can be called off main thread.
   static double ReduceTimePrecisionAsMSecs(double aTime);