Bug 1004365 part 3b.1 - Add % operator to TimeDuration; r=froydnj

xpcom/ds/TimeStamp.h

@@ -129,6 +129,10 @@ public:
   double operator/(const TimeDuration& aOther) const {
     return static_cast<double>(mValue) / aOther.mValue;
   }
+  TimeDuration operator%(const TimeDuration& aOther) const {
+    MOZ_ASSERT(aOther.mValue != 0, "Division by zero");
+    return TimeDuration::FromTicks(mValue % aOther.mValue);
+  }
 
   bool operator<(const TimeDuration& aOther) const {
     return mValue < aOther.mValue;