diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index c5ed38dc27..744b3ab8d3 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -318,6 +318,8 @@ nsGlobalWindow::DOMMinTimeoutValue() const {
 // nsTimerImpl.h for details.
 #define DOM_MAX_TIMEOUT_VALUE    DELAY_INTERVAL_LIMIT
 
+#define MEMORY_PRESSURE_OBSERVER_TOPIC "memory-pressure"
+
 // The interval at which we execute idle callbacks
 static uint32_t gThrottledIdlePeriodLength;
 
@@ -1525,6 +1527,8 @@ nsGlobalWindow::nsGlobalWindow(nsGlobalWindow *aOuterWindow)
         // Watch for dom-storage2-changed so we can fire storage
         // events. Use a strong reference.
         os->AddObserver(mObserver, "dom-storage2-changed", false);
+
+        os->AddObserver(mObserver, MEMORY_PRESSURE_OBSERVER_TOPIC, false);
       }
 
       Preferences::AddStrongObserver(mObserver, "intl.accept_languages");
@@ -1840,6 +1844,7 @@ nsGlobalWindow::CleanUp()
     if (os) {
       os->RemoveObserver(mObserver, NS_IOSERVICE_OFFLINE_STATUS_TOPIC);
       os->RemoveObserver(mObserver, "dom-storage2-changed");
+      os->RemoveObserver(mObserver, MEMORY_PRESSURE_OBSERVER_TOPIC);
     }
 
     if (mIdleService) {
@@ -11702,6 +11707,13 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
     return NS_OK;
   }
 
+  if (!nsCRT::strcmp(aTopic, MEMORY_PRESSURE_OBSERVER_TOPIC)) {
+    if (mPerformance) {
+      mPerformance->MemoryPressure();
+    }
+    return NS_OK;
+  }
+
   if (!nsCRT::strcmp(aTopic, OBSERVER_TOPIC_IDLE)) {
     mCurrentlyIdle = true;
     if (IsFrozen()) {
diff --git a/dom/performance/Performance.cpp b/dom/performance/Performance.cpp
index 9a1d134626..09c38fef42 100755
--- a/dom/performance/Performance.cpp
+++ b/dom/performance/Performance.cpp
@@ -262,11 +262,6 @@ already_AddRefed<PerformanceMark> Performance::Mark(
   const PerformanceMarkOptions& aMarkOptions,
   ErrorResult& aRv)
 {
-  // Don't add the entry if the buffer is full. XXX should be removed by bug 1159003.
-  if (mUserEntries.Length() >= mResourceTimingBufferSize) {
-    return nullptr;
-  }
-
   nsCOMPtr<nsIGlobalObject> parent = GetParentObject();
   if (!parent || parent->IsDying() || !parent->GetGlobalJSObject()) {
     aRv.Throw(NS_ERROR_DOM_UT_UNAVAILABLE_GLOBAL_OBJECT);
@@ -490,12 +485,6 @@ Performance::Measure(JSContext* aCx,
                      const Optional<nsAString>& aEndMark,
                      ErrorResult& aRv)
 {
-  // Don't add the entry if the buffer is full. XXX should be removed by bug
-  // 1159003.
-  if (mUserEntries.Length() >= mResourceTimingBufferSize) {
-    return nullptr;
-  }
-
   const PerformanceMeasureOptions* options = nullptr;
   if (aStartOrMeasureOptions.IsPerformanceMeasureOptions()) {
     options = &aStartOrMeasureOptions.GetAsPerformanceMeasureOptions();
@@ -553,7 +542,7 @@ Performance::Measure(JSContext* aCx,
   }
 
   RefPtr<PerformanceMeasure> performanceMeasure = new PerformanceMeasure(
-      GetAsISupports(), aName, startTime, endTime, detail);
+      GetParentObject(), aName, startTime, endTime, detail);
   InsertUserEntry(performanceMeasure);
 
   return performanceMeasure.forget();
@@ -753,5 +742,11 @@ Performance::IsObserverEnabled(JSContext* aCx, JSObject* aGlobal)
   return runnable->Dispatch() && runnable->IsEnabled();
 }
 
+void
+Performance::MemoryPressure()
+{
+  mUserEntries.Clear();
+}
+
 } // dom namespace
 } // mozilla namespace
diff --git a/dom/performance/Performance.h b/dom/performance/Performance.h
index 2108e1e394..a8ec1c484c 100644
--- a/dom/performance/Performance.h
+++ b/dom/performance/Performance.h
@@ -124,6 +124,8 @@ public:
     return false;
   }
 
+  void MemoryPressure();
+
 protected:
   Performance();
   explicit Performance(nsPIDOMWindowInner* aWindow);
@@ -136,8 +138,6 @@ protected:
   void ClearUserEntries(const Optional<nsAString>& aEntryName,
                         const nsAString& aEntryType);
 
-  virtual nsISupports* GetAsISupports() = 0;
-
   virtual void DispatchBufferFullEvent() = 0;
 
   virtual TimeStamp CreationTimeStamp() const = 0;
@@ -167,11 +167,14 @@ protected:
   nsTObserverArray<PerformanceObserver*> mObservers;
 
 protected:
-  nsTArray<RefPtr<PerformanceEntry>> mUserEntries;
-  nsTArray<RefPtr<PerformanceEntry>> mResourceEntries;
+  static const uint64_t kDefaultResourceTimingBufferSize = 1500;
+
+  // When kDefaultResourceTimingBufferSize is increased or removed, these should
+  // be changed to use SegmentedVector
+  AutoTArray<RefPtr<PerformanceEntry>, kDefaultResourceTimingBufferSize> mUserEntries;
+  AutoTArray<RefPtr<PerformanceEntry>, kDefaultResourceTimingBufferSize> mResourceEntries;
 
   uint64_t mResourceTimingBufferSize;
-  static const uint64_t kDefaultResourceTimingBufferSize = 1500;
   bool mPendingNotificationObserversTask;
 
   RefPtr<PerformanceService> mPerformanceService;
diff --git a/dom/performance/PerformanceMainThread.h b/dom/performance/PerformanceMainThread.h
index 702483e9de..735522c502 100644
--- a/dom/performance/PerformanceMainThread.h
+++ b/dom/performance/PerformanceMainThread.h
@@ -65,11 +65,6 @@ public:
 protected:
   ~PerformanceMainThread();
 
-  nsISupports* GetAsISupports() override
-  {
-    return this;
-  }
-
   void InsertUserEntry(PerformanceEntry* aEntry) override;
 
   DOMHighResTimeStamp
diff --git a/dom/performance/PerformanceWorker.h b/dom/performance/PerformanceWorker.h
index 3604e6874f..8dcbf1f202 100644
--- a/dom/performance/PerformanceWorker.h
+++ b/dom/performance/PerformanceWorker.h
@@ -65,11 +65,6 @@ public:
 protected:
   ~PerformanceWorker();
 
-  nsISupports* GetAsISupports() override
-  {
-    return nullptr;
-  }
-
   void InsertUserEntry(PerformanceEntry* aEntry) override;
 
   void DispatchBufferFullEvent() override
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index a7a4929f3b..29c2263cd1 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -6441,14 +6441,23 @@ WorkerPrivate::MemoryPressureInternal()
 {
   AssertIsOnWorkerThread();
 
-  RefPtr<Console> console = mScope ? mScope->GetConsoleIfExists() : nullptr;
-  if (console) {
-    console->ClearStorage();
+  if (mScope) {
+    RefPtr<Console> console = mScope->GetConsoleIfExists();
+    if (console) {
+      console->ClearStorage();
+    }
+
+    RefPtr<Performance> performance = mScope->GetPerformanceIfExists();
+    if (performance) {
+      performance->MemoryPressure();
+    }
   }
 
-  console = mDebuggerScope ? mDebuggerScope->GetConsoleIfExists() : nullptr;
-  if (console) {
-    console->ClearStorage();
+  if (mDebuggerScope) {
+    RefPtr<Console> console = mDebuggerScope->GetConsoleIfExists();
+    if (console) {
+      console->ClearStorage();
+    }
   }
 
   for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
diff --git a/dom/workers/WorkerScope.h b/dom/workers/WorkerScope.h
index 01bae5cc11..8e886f6cb2 100644
--- a/dom/workers/WorkerScope.h
+++ b/dom/workers/WorkerScope.h
@@ -157,6 +157,11 @@ public:
 
   Performance* GetPerformance();
 
+  Performance* GetPerformanceIfExists() const
+  {
+    return mPerformance;
+  }
+
   already_AddRefed<Promise>
   Fetch(const RequestOrUSVString& aInput, const RequestInit& aInit, ErrorResult& aRv);