2 files changed, 4 insertions, 23 deletions
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index bd8a33032..8848e881a 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -2419,8 +2419,6 @@ WorkerPrivateParent<Derived>::WorkerPrivateParent(
     MOZ_ASSERT_IF(mIsChromeWorker, mIsSecureContext);
 
     MOZ_ASSERT(IsDedicatedWorker());
-    mNowBaseTimeStamp = aParent->NowBaseTimeStamp();
-    mNowBaseTimeHighRes = aParent->NowBaseTime();
 
     if (aParent->mParentFrozen) {
       Freeze(nullptr);
@@ -2451,18 +2449,6 @@ WorkerPrivateParent<Derived>::WorkerPrivateParent(
                  .creationOptions().setSecureContext(true);
     }
 
-    if (IsDedicatedWorker() && mLoadInfo.mWindow &&
-        mLoadInfo.mWindow->GetPerformance()) {
-      mNowBaseTimeStamp = mLoadInfo.mWindow->GetPerformance()->GetDOMTiming()->
-        GetNavigationStartTimeStamp();
-      mNowBaseTimeHighRes =
-      mLoadInfo.mWindow->GetPerformance()->GetDOMTiming()->
-        GetNavigationStartHighRes();
-    } else {
-      mNowBaseTimeStamp = CreationTimeStamp();
-      mNowBaseTimeHighRes = CreationTime();
-    }
-
     // Our parent can get suspended after it initiates the async creation
     // of a new worker thread.  In this case suspend the new worker as well.
     if (mLoadInfo.mWindow && mLoadInfo.mWindow->IsSuspended()) {
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index 465c0f9a3..28283bed7 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -216,8 +216,6 @@ private:
   WorkerType mWorkerType;
   TimeStamp mCreationTimeStamp;
   DOMHighResTimeStamp mCreationTimeHighRes;
-  TimeStamp mNowBaseTimeStamp;
-  DOMHighResTimeStamp mNowBaseTimeHighRes;
 
 protected:
   // The worker is owned by its thread, which is represented here.  This is set
@@ -579,14 +577,11 @@ public:
     return mCreationTimeHighRes;
   }
 
-  TimeStamp NowBaseTimeStamp() const
+  DOMHighResTimeStamp TimeStampToDOMHighRes(const TimeStamp& aTimeStamp) const
   {
-    return mNowBaseTimeStamp;
-  }
-
-  DOMHighResTimeStamp NowBaseTime() const
-  {
-    return mNowBaseTimeHighRes;
+    MOZ_ASSERT(!aTimeStamp.IsNull());
+    TimeDuration duration = aTimeStamp - mCreationTimeStamp;
+    return duration.ToMilliseconds();
   }
 
   nsIPrincipal*