diff --git a/dom/quota/ActorsParent.cpp b/dom/quota/ActorsParent.cpp
index 0298fc4af97c..e31d631ff96c 100644
--- a/dom/quota/ActorsParent.cpp
+++ b/dom/quota/ActorsParent.cpp
@@ -36,6 +36,7 @@
 #include "mozilla/dom/quota/PQuotaParent.h"
 #include "mozilla/dom/quota/PQuotaRequestParent.h"
 #include "mozilla/dom/quota/PQuotaUsageRequestParent.h"
+#include "mozilla/dom/StorageActivityService.h"
 #include "mozilla/ipc/BackgroundParent.h"
 #include "mozilla/ipc/BackgroundUtils.h"
 #include "mozilla/IntegerRange.h"
@@ -3025,6 +3026,11 @@ QuotaObject::LockedMaybeUpdateSize(int64_t aSize, bool aTruncate)
 
   quotaManager->mQuotaMutex.AssertCurrentThreadOwns();
 
+  if (mWritingDone == false && mOriginInfo) {
+    mWritingDone = true;
+    StorageActivityService::SendActivity(mOriginInfo->mOrigin);
+  }
+
   if (mQuotaCheckDisabled) {
     return true;
   }
diff --git a/dom/quota/QuotaObject.h b/dom/quota/QuotaObject.h
index fba31edbf2cf..2dfbd9667fe9 100644
--- a/dom/quota/QuotaObject.h
+++ b/dom/quota/QuotaObject.h
@@ -56,6 +56,7 @@ private:
     , mPath(aPath)
     , mSize(aSize)
     , mQuotaCheckDisabled(false)
+    , mWritingDone(false)
   {
     MOZ_COUNT_CTOR(QuotaObject);
   }
@@ -86,6 +87,7 @@ private:
   int64_t mSize;
 
   bool mQuotaCheckDisabled;
+  bool mWritingDone;
 };
 
 END_QUOTA_NAMESPACE
diff --git a/dom/storage/StorageActivityService.cpp b/dom/storage/StorageActivityService.cpp
index 9fe07382345b..edc56c133a13 100644
--- a/dom/storage/StorageActivityService.cpp
+++ b/dom/storage/StorageActivityService.cpp
@@ -64,6 +64,34 @@ StorageActivityService::SendActivity(const mozilla::ipc::PrincipalInfo& aPrincip
   SystemGroup::Dispatch(TaskCategory::Other, r.forget());
 }
 
+/* static */ void
+StorageActivityService::SendActivity(const nsACString& aOrigin)
+{
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  nsCString origin;
+  origin.Assign(aOrigin);
+
+  RefPtr<Runnable> r = NS_NewRunnableFunction(
+    "StorageActivityService::SendActivity",
+    [origin] () {
+      MOZ_ASSERT(NS_IsMainThread());
+
+      RefPtr<StorageActivityService> service = GetOrCreate();
+      if (NS_WARN_IF(!service)) {
+        return;
+      }
+
+      service->SendActivityInternal(origin);
+    });
+
+  if (NS_IsMainThread()) {
+    Unused << r->Run();
+  } else {
+    SystemGroup::Dispatch(TaskCategory::Other, r.forget());
+  }
+}
+
 /* static */ already_AddRefed<StorageActivityService>
 StorageActivityService::GetOrCreate()
 {
@@ -118,8 +146,15 @@ StorageActivityService::SendActivityInternal(nsIPrincipal* aPrincipal)
     return;
   }
 
-  mActivities.Put(origin, PR_Now());
+  SendActivityInternal(origin);
+}
 
+void
+StorageActivityService::SendActivityInternal(const nsACString& aOrigin)
+{
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  mActivities.Put(aOrigin, PR_Now());
   MaybeStartTimer();
 }
 
diff --git a/dom/storage/StorageActivityService.h b/dom/storage/StorageActivityService.h
index 815831c72e54..84f2d303e5e7 100644
--- a/dom/storage/StorageActivityService.h
+++ b/dom/storage/StorageActivityService.h
@@ -39,6 +39,10 @@ public:
   static void
   SendActivity(const mozilla::ipc::PrincipalInfo& aPrincipalInfo);
 
+  // Thread-safe but for parent process only!
+  static void
+  SendActivity(const nsACString& aOrigin);
+
   // Used by XPCOM. Don't use it, use SendActivity() instead.
   static already_AddRefed<StorageActivityService>
   GetOrCreate();
@@ -50,6 +54,9 @@ private:
   void
   SendActivityInternal(nsIPrincipal* aPrincipal);
 
+  void
+  SendActivityInternal(const nsACString& aOrigin);
+
   void
   SendActivityToParent(nsIPrincipal* aPrincipal);