diff --git a/caps/DomainPolicy.cpp b/caps/DomainPolicy.cpp
index 48dc4f8ca268..c4c9118dbe04 100644
--- a/caps/DomainPolicy.cpp
+++ b/caps/DomainPolicy.cpp
@@ -29,11 +29,8 @@ static nsresult BroadcastDomainSetChange(DomainSetType aSetType,
     return NS_OK;
   }
 
-  Maybe<URIParams> uri;
-  SerializeURI(aDomain, uri);
-
   for (uint32_t i = 0; i < parents.Length(); i++) {
-    Unused << parents[i]->SendDomainSetChanged(aSetType, aChangeType, uri);
+    Unused << parents[i]->SendDomainSetChanged(aSetType, aChangeType, aDomain);
   }
   return NS_OK;
 }
@@ -118,10 +115,13 @@ void DomainPolicy::CloneDomainPolicy(DomainPolicyClone* aClone) {
   mSuperAllowlist->CloneSet(&aClone->superAllowlist());
 }
 
-static void CopyURIs(const nsTArray<URIParams>& aDomains, nsIDomainSet* aSet) {
+static void CopyURIs(const nsTArray<RefPtr<nsIURI>>& aDomains,
+                     nsIDomainSet* aSet) {
   for (uint32_t i = 0; i < aDomains.Length(); i++) {
-    nsCOMPtr<nsIURI> uri = DeserializeURI(aDomains[i]);
-    aSet->Add(uri);
+    if (NS_WARN_IF(!aDomains[i])) {
+      continue;
+    }
+    aSet->Add(aDomains[i]);
   }
 }
 
@@ -149,8 +149,9 @@ DomainSet::Add(nsIURI* aDomain) {
   nsCOMPtr<nsIURI> clone = GetCanonicalClone(aDomain);
   NS_ENSURE_TRUE(clone, NS_ERROR_FAILURE);
   mHashTable.PutEntry(clone);
-  if (XRE_IsParentProcess())
+  if (XRE_IsParentProcess()) {
     return BroadcastDomainSetChange(mType, ADD_DOMAIN, aDomain);
+  }
 
   return NS_OK;
 }
@@ -160,8 +161,9 @@ DomainSet::Remove(nsIURI* aDomain) {
   nsCOMPtr<nsIURI> clone = GetCanonicalClone(aDomain);
   NS_ENSURE_TRUE(clone, NS_ERROR_FAILURE);
   mHashTable.RemoveEntry(clone);
-  if (XRE_IsParentProcess())
+  if (XRE_IsParentProcess()) {
     return BroadcastDomainSetChange(mType, REMOVE_DOMAIN, aDomain);
+  }
 
   return NS_OK;
 }
@@ -169,8 +171,9 @@ DomainSet::Remove(nsIURI* aDomain) {
 NS_IMETHODIMP
 DomainSet::Clear() {
   mHashTable.Clear();
-  if (XRE_IsParentProcess())
+  if (XRE_IsParentProcess()) {
     return BroadcastDomainSetChange(mType, CLEAR_DOMAINS);
+  }
 
   return NS_OK;
 }
@@ -212,14 +215,10 @@ DomainSet::ContainsSuperDomain(nsIURI* aDomain, bool* aContains) {
   return NS_OK;
 }
 
-void DomainSet::CloneSet(nsTArray<URIParams>* aDomains) {
+void DomainSet::CloneSet(nsTArray<RefPtr<nsIURI>>* aDomains) {
   for (auto iter = mHashTable.Iter(); !iter.Done(); iter.Next()) {
     nsIURI* key = iter.Get()->GetKey();
-
-    URIParams uri;
-    SerializeURI(key, uri);
-
-    aDomains->AppendElement(uri);
+    aDomains->AppendElement(key);
   }
 }
 
diff --git a/caps/DomainPolicy.h b/caps/DomainPolicy.h
index cad67df47bcf..105b7fc1a07d 100644
--- a/caps/DomainPolicy.h
+++ b/caps/DomainPolicy.h
@@ -13,10 +13,6 @@
 
 namespace mozilla {
 
-namespace ipc {
-class URIParams;
-}  // namespace ipc
-
 enum DomainSetChangeType {
   ACTIVATE_POLICY,
   DEACTIVATE_POLICY,
@@ -40,7 +36,7 @@ class DomainSet final : public nsIDomainSet {
 
   explicit DomainSet(DomainSetType aType) : mType(aType) {}
 
-  void CloneSet(nsTArray<mozilla::ipc::URIParams>* aDomains);
+  void CloneSet(nsTArray<RefPtr<nsIURI>>* aDomains);
 
  protected:
   virtual ~DomainSet() {}
diff --git a/docshell/base/nsDefaultURIFixup.cpp b/docshell/base/nsDefaultURIFixup.cpp
index 3ca219a6e331..6009db858a29 100644
--- a/docshell/base/nsDefaultURIFixup.cpp
+++ b/docshell/base/nsDefaultURIFixup.cpp
@@ -389,7 +389,7 @@ nsDefaultURIFixup::KeywordToURI(const nsACString& aKeyword,
     }
 
     RefPtr<nsIInputStream> postData;
-    Maybe<mozilla::ipc::URIParams> uri;
+    RefPtr<nsIURI> uri;
     nsAutoString providerName;
     if (!contentChild->SendKeywordToURI(keyword, aIsPrivateContext,
                                         &providerName, &postData, &uri)) {
@@ -403,8 +403,7 @@ nsDefaultURIFixup::KeywordToURI(const nsACString& aKeyword,
       postData.forget(aPostData);
     }
 
-    nsCOMPtr<nsIURI> temp = DeserializeURI(uri);
-    info->mPreferredURI = std::move(temp);
+    info->mPreferredURI = uri.forget();
     return NS_OK;
   }
 
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 504b82f2085c..054bf815938a 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -3682,11 +3682,9 @@ nsDocShell::DisplayLoadError(nsresult aError, nsIURI* aURI,
       } else {
         mozilla::dom::ContentChild* cc =
             mozilla::dom::ContentChild::GetSingleton();
-        mozilla::ipc::URIParams uri;
-        SerializeURI(aURI, uri);
-        cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HSTS, uri, flags,
+        cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HSTS, aURI, flags,
                             mOriginAttributes, &isStsHost);
-        cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HPKP, uri, flags,
+        cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HPKP, aURI, flags,
                             mOriginAttributes, &isPinnedHost);
       }
 
@@ -8131,10 +8129,7 @@ void nsDocShell::CopyFavicon(nsIURI* aOldURI, nsIURI* aNewURI,
   if (XRE_IsContentProcess()) {
     dom::ContentChild* contentChild = dom::ContentChild::GetSingleton();
     if (contentChild) {
-      mozilla::ipc::URIParams oldURI, newURI;
-      SerializeURI(aOldURI, oldURI);
-      SerializeURI(aNewURI, newURI);
-      contentChild->SendCopyFavicon(oldURI, newURI,
+      contentChild->SendCopyFavicon(aOldURI, aNewURI,
                                     IPC::Principal(aLoadingPrincipal),
                                     aInPrivateBrowsing);
     }
diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
index 0c4c247f0dc7..1935388d4313 100644
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -1809,11 +1809,9 @@ void Document::GetFailedCertSecurityInfo(FailedCertSecurityInfo& aInfo,
   if (XRE_IsContentProcess()) {
     ContentChild* cc = ContentChild::GetSingleton();
     MOZ_ASSERT(cc);
-    mozilla::ipc::URIParams uri;
-    SerializeURI(aURI, uri);
-    cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HSTS, uri, flags, attrs,
+    cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HSTS, aURI, flags, attrs,
                         &aInfo.mHasHSTS);
-    cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HPKP, uri, flags, attrs,
+    cc->SendIsSecureURI(nsISiteSecurityService::HEADER_HPKP, aURI, flags, attrs,
                         &aInfo.mHasHPKP);
   } else {
     nsCOMPtr<nsISiteSecurityService> sss =
diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index 898814ed5103..0ad93052c7df 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -934,9 +934,6 @@ nsresult ContentChild::ProvideWindowCommon(
       return rv;
     }
 
-    Maybe<URIParams> uriToLoad;
-    SerializeURI(aURI, uriToLoad);
-
     if (name.LowerCaseEqualsLiteral("_blank")) {
       name = EmptyString();
     }
@@ -944,7 +941,7 @@ nsresult ContentChild::ProvideWindowCommon(
     MOZ_DIAGNOSTIC_ASSERT(!nsContentUtils::IsSpecialName(name));
 
     Unused << SendCreateWindowInDifferentProcess(
-        aTabOpener, aChromeFlags, aCalledFromJS, aWidthSpecified, uriToLoad,
+        aTabOpener, aChromeFlags, aCalledFromJS, aWidthSpecified, aURI,
         features, fullZoom, name, triggeringPrincipal, csp, referrerInfo);
 
     // We return NS_ERROR_ABORT, so that the caller knows that we've abandoned
@@ -1192,13 +1189,7 @@ nsresult ContentChild::ProvideWindowCommon(
       return rv;
     }
 
-    Maybe<URIParams> uriToLoad;
-    if (aURI) {
-      SerializeURI(aURI, uriToLoad);
-    }
-
-    SendCreateWindow(aTabOpener, newChild, aChromeFlags, aCalledFromJS,
-                     aWidthSpecified, uriToLoad, features, fullZoom,
+    SendCreateWindow(aTabOpener, newChild, aChromeFlags, aCalledFromJS, aWidthSpecified, aURI, features, fullZoom,
                      Principal(triggeringPrincipal), csp, referrerInfo,
                      std::move(resolve), std::move(reject));
   }
@@ -1401,7 +1392,7 @@ void ContentChild::InitXPCOM(
   }
 
   // The stylesheet cache is not ready yet. Store this URL for future use.
-  nsCOMPtr<nsIURI> ucsURL = DeserializeURI(aXPCOMInit.userContentSheetURL());
+  nsCOMPtr<nsIURI> ucsURL = aXPCOMInit.userContentSheetURL();
   GlobalStyleSheetCache::SetUserContentCSSURL(ucsURL);
 
   GfxInfoBase::SetFeatureStatus(aXPCOMInit.gfxFeatureStatus());
@@ -2365,7 +2356,7 @@ mozilla::ipc::IPCResult ContentChild::RecvNotifyVisited(
     return IPC_OK();
   }
   for (const VisitedQueryResult& result : aURIs) {
-    nsCOMPtr<nsIURI> newURI = DeserializeURI(result.uri());
+    nsCOMPtr<nsIURI> newURI = result.uri();
     if (!newURI) {
       return IPC_FAIL_NO_REASON(this);
     }
@@ -2747,38 +2738,35 @@ mozilla::ipc::IPCResult ContentChild::RecvNotifyIdleObserver(
 }
 
 mozilla::ipc::IPCResult ContentChild::RecvLoadAndRegisterSheet(
-    const URIParams& aURI, const uint32_t& aType) {
-  nsCOMPtr<nsIURI> uri = DeserializeURI(aURI);
-  if (!uri) {
+    nsIURI* aURI, const uint32_t& aType) {
+  if (!aURI) {
     return IPC_OK();
   }
 
   nsStyleSheetService* sheetService = nsStyleSheetService::GetInstance();
   if (sheetService) {
-    sheetService->LoadAndRegisterSheet(uri, aType);
+    sheetService->LoadAndRegisterSheet(aURI, aType);
   }
 
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult ContentChild::RecvUnregisterSheet(
-    const URIParams& aURI, const uint32_t& aType) {
-  nsCOMPtr<nsIURI> uri = DeserializeURI(aURI);
-  if (!uri) {
+    nsIURI* aURI, const uint32_t& aType) {
+  if (!aURI) {
     return IPC_OK();
   }
 
   nsStyleSheetService* sheetService = nsStyleSheetService::GetInstance();
   if (sheetService) {
-    sheetService->UnregisterSheet(uri, aType);
+    sheetService->UnregisterSheet(aURI, aType);
   }
 
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult ContentChild::RecvDomainSetChanged(
-    const uint32_t& aSetType, const uint32_t& aChangeType,
-    const Maybe<URIParams>& aDomain) {
+    const uint32_t& aSetType, const uint32_t& aChangeType, nsIURI* aDomain) {
   if (aChangeType == ACTIVATE_POLICY) {
     if (mPolicy) {
       return IPC_OK();
@@ -2827,16 +2815,14 @@ mozilla::ipc::IPCResult ContentChild::RecvDomainSetChanged(
 
   MOZ_ASSERT(set);
 
-  nsCOMPtr<nsIURI> uri = DeserializeURI(aDomain);
-
   switch (aChangeType) {
     case ADD_DOMAIN:
-      NS_ENSURE_TRUE(uri, IPC_FAIL_NO_REASON(this));
-      set->Add(uri);
+      NS_ENSURE_TRUE(aDomain, IPC_FAIL_NO_REASON(this));
+      set->Add(aDomain);
       break;
     case REMOVE_DOMAIN:
-      NS_ENSURE_TRUE(uri, IPC_FAIL_NO_REASON(this));
-      set->Remove(uri);
+      NS_ENSURE_TRUE(aDomain, IPC_FAIL_NO_REASON(this));
+      set->Remove(aDomain);
       break;
     case CLEAR_DOMAINS:
       set->Clear();
@@ -3263,7 +3249,7 @@ bool ContentChild::DeallocPURLClassifierChild(PURLClassifierChild* aActor) {
 }
 
 PURLClassifierLocalChild* ContentChild::AllocPURLClassifierLocalChild(
-    const URIParams& aUri, const nsTArray<IPCURLClassifierFeature>& aFeatures) {
+    nsIURI* aUri, const nsTArray<IPCURLClassifierFeature>& aFeatures) {
   return new URLClassifierLocalChild();
 }
 
@@ -3274,8 +3260,7 @@ bool ContentChild::DeallocPURLClassifierLocalChild(
   return true;
 }
 
-PLoginReputationChild* ContentChild::AllocPLoginReputationChild(
-    const URIParams& aUri) {
+PLoginReputationChild* ContentChild::AllocPLoginReputationChild(nsIURI* aUri) {
   return new PLoginReputationChild();
 }
 
diff --git a/dom/ipc/ContentChild.h b/dom/ipc/ContentChild.h
index 0eb0a75e5e04..2d37125161c6 100644
--- a/dom/ipc/ContentChild.h
+++ b/dom/ipc/ContentChild.h
@@ -60,10 +60,6 @@ using mozilla::loader::PScriptCacheChild;
 bool IsDevelopmentBuild();
 #endif /* !XP_WIN */
 
-namespace ipc {
-class URIParams;
-}  // namespace ipc
-
 namespace dom {
 
 namespace ipc {
@@ -88,7 +84,6 @@ class ContentChild final
   typedef mozilla::dom::ClonedMessageData ClonedMessageData;
   typedef mozilla::ipc::FileDescriptor FileDescriptor;
   typedef mozilla::ipc::PFileDescriptorSetChild PFileDescriptorSetChild;
-  typedef mozilla::ipc::URIParams URIParams;
 
   friend class PContentChild;
 
@@ -421,10 +416,10 @@ class ContentChild final
 
   mozilla::ipc::IPCResult RecvMinimizeMemoryUsage();
 
-  mozilla::ipc::IPCResult RecvLoadAndRegisterSheet(const URIParams& aURI,
+  mozilla::ipc::IPCResult RecvLoadAndRegisterSheet(nsIURI* aURI,
                                                    const uint32_t& aType);
 
-  mozilla::ipc::IPCResult RecvUnregisterSheet(const URIParams& aURI,
+  mozilla::ipc::IPCResult RecvUnregisterSheet(nsIURI* aURI,
                                               const uint32_t& aType);
 
   void AddIdleObserver(nsIObserver* aObserver, uint32_t aIdleTimeInS);
@@ -439,7 +434,7 @@ class ContentChild final
 
   mozilla::ipc::IPCResult RecvDomainSetChanged(const uint32_t& aSetType,
                                                const uint32_t& aChangeType,
-                                               const Maybe<URIParams>& aDomain);
+                                               nsIURI* aDomain);
 
   mozilla::ipc::IPCResult RecvShutdown();
 
@@ -601,11 +596,10 @@ class ContentChild final
 
   // PURLClassifierLocalChild
   PURLClassifierLocalChild* AllocPURLClassifierLocalChild(
-      const URIParams& aUri,
-      const nsTArray<IPCURLClassifierFeature>& aFeatures);
+      nsIURI* aUri, const nsTArray<IPCURLClassifierFeature>& aFeatures);
   bool DeallocPURLClassifierLocalChild(PURLClassifierLocalChild* aActor);
 
-  PLoginReputationChild* AllocPLoginReputationChild(const URIParams& aUri);
+  PLoginReputationChild* AllocPLoginReputationChild(nsIURI* aUri);
 
   bool DeallocPLoginReputationChild(PLoginReputationChild* aActor);
 
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 306a575bbece..f93d3a83fe31 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -2398,9 +2398,9 @@ bool ContentParent::InitInternal(ProcessPriority aInitialPriority) {
   // send the file URL instead.
   auto* sheetCache = GlobalStyleSheetCache::Singleton();
   if (StyleSheet* ucs = sheetCache->GetUserContentSheet()) {
-    SerializeURI(ucs->GetSheetURI(), xpcomInit.userContentSheetURL());
+    xpcomInit.userContentSheetURL() = ucs->GetSheetURI();
   } else {
-    SerializeURI(nullptr, xpcomInit.userContentSheetURL());
+    xpcomInit.userContentSheetURL() = nullptr;
   }
 
   // 1. Build ContentDeviceData first, as it may affect some gfxVars.
@@ -2528,22 +2528,17 @@ bool ContentParent::InitInternal(ProcessPriority aInitialPriority) {
     // shouldn't matter which we look at.
 
     for (StyleSheet* sheet : *sheetService->AgentStyleSheets()) {
-      URIParams uri;
-      SerializeURI(sheet->GetSheetURI(), uri);
-      Unused << SendLoadAndRegisterSheet(uri,
+      Unused << SendLoadAndRegisterSheet(sheet->GetSheetURI(),
                                          nsIStyleSheetService::AGENT_SHEET);
     }
 
     for (StyleSheet* sheet : *sheetService->UserStyleSheets()) {
-      URIParams uri;
-      SerializeURI(sheet->GetSheetURI(), uri);
-      Unused << SendLoadAndRegisterSheet(uri, nsIStyleSheetService::USER_SHEET);
+      Unused << SendLoadAndRegisterSheet(sheet->GetSheetURI(),
+                                         nsIStyleSheetService::USER_SHEET);
     }
 
     for (StyleSheet* sheet : *sheetService->AuthorStyleSheets()) {
-      URIParams uri;
-      SerializeURI(sheet->GetSheetURI(), uri);
-      Unused << SendLoadAndRegisterSheet(uri,
+      Unused << SendLoadAndRegisterSheet(sheet->GetSheetURI(),
                                          nsIStyleSheetService::AUTHOR_SHEET);
     }
   }
@@ -2832,14 +2827,13 @@ mozilla::ipc::IPCResult ContentParent::RecvGetExternalClipboardFormats(
   return IPC_OK();
 }
 
-mozilla::ipc::IPCResult ContentParent::RecvPlaySound(const URIParams& aURI) {
-  nsCOMPtr<nsIURI> soundURI = DeserializeURI(aURI);
+mozilla::ipc::IPCResult ContentParent::RecvPlaySound(nsIURI* aURI) {
   // If the check here fails, it can only mean that this message was spoofed.
-  if (!soundURI || !soundURI->SchemeIs("chrome")) {
+  if (!aURI || !aURI->SchemeIs("chrome")) {
     // PlaySound only accepts a valid chrome URI.
     return IPC_FAIL_NO_REASON(this);
   }
-  nsCOMPtr<nsIURL> soundURL(do_QueryInterface(soundURI));
+  nsCOMPtr<nsIURL> soundURL(do_QueryInterface(aURI));
   if (!soundURL) {
     return IPC_OK();
   }
@@ -3642,14 +3636,12 @@ bool ContentParent::DeallocPParentToChildStreamParent(
 
 already_AddRefed<PExternalHelperAppParent>
 ContentParent::AllocPExternalHelperAppParent(
-    const Maybe<URIParams>& uri,
-    const Maybe<mozilla::net::LoadInfoArgs>& aLoadInfoArgs,
+    nsIURI* uri, const Maybe<mozilla::net::LoadInfoArgs>& aLoadInfoArgs,
     const nsCString& aMimeContentType, const nsCString& aContentDisposition,
     const uint32_t& aContentDispositionHint,
     const nsString& aContentDispositionFilename, const bool& aForceSave,
     const int64_t& aContentLength, const bool& aWasFileChannel,
-    const Maybe<URIParams>& aReferrer,
-    const MaybeDiscarded<BrowsingContext>& aContext,
+    nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
     const bool& aShouldCloseWindow) {
   RefPtr<ExternalHelperAppParent> parent = new ExternalHelperAppParent(
       uri, aContentLength, aWasFileChannel, aContentDisposition,
@@ -3658,14 +3650,13 @@ ContentParent::AllocPExternalHelperAppParent(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvPExternalHelperAppConstructor(
-    PExternalHelperAppParent* actor, const Maybe<URIParams>& uri,
+    PExternalHelperAppParent* actor, nsIURI* uri,
     const Maybe<LoadInfoArgs>& loadInfoArgs, const nsCString& aMimeContentType,
     const nsCString& aContentDisposition,
     const uint32_t& aContentDispositionHint,
     const nsString& aContentDispositionFilename, const bool& aForceSave,
     const int64_t& aContentLength, const bool& aWasFileChannel,
-    const Maybe<URIParams>& aReferrer,
-    const MaybeDiscarded<BrowsingContext>& aContext,
+    nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
     const bool& aShouldCloseWindow) {
   BrowsingContext* context = aContext.IsDiscarded() ? nullptr : aContext.get();
   static_cast<ExternalHelperAppParent*>(actor)->Init(
@@ -3738,46 +3729,43 @@ mozilla::ipc::IPCResult ContentParent::RecvPSpeechSynthesisConstructor(
 #endif
 
 mozilla::ipc::IPCResult ContentParent::RecvStartVisitedQueries(
-    const nsTArray<URIParams>& aUris) {
+    const nsTArray<RefPtr<nsIURI>>& aUris) {
   nsCOMPtr<IHistory> history = services::GetHistoryService();
   if (!history) {
     return IPC_OK();
   }
   for (const auto& params : aUris) {
-    nsCOMPtr<nsIURI> uri = DeserializeURI(params);
-    if (NS_WARN_IF(!uri)) {
+    if (NS_WARN_IF(!params)) {
       continue;
     }
-    history->RegisterVisitedCallback(uri, nullptr);
+    history->RegisterVisitedCallback(params, nullptr);
   }
   return IPC_OK();
 }
 
-mozilla::ipc::IPCResult ContentParent::RecvSetURITitle(const URIParams& uri,
+mozilla::ipc::IPCResult ContentParent::RecvSetURITitle(nsIURI* uri,
                                                        const nsString& title) {
-  nsCOMPtr<nsIURI> ourURI = DeserializeURI(uri);
-  if (!ourURI) {
+  if (!uri) {
     return IPC_FAIL_NO_REASON(this);
   }
   nsCOMPtr<IHistory> history = services::GetHistoryService();
   if (history) {
-    history->SetURITitle(ourURI, title);
+    history->SetURITitle(uri, title);
   }
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvIsSecureURI(
-    const uint32_t& aType, const URIParams& aURI, const uint32_t& aFlags,
+    const uint32_t& aType, nsIURI* aURI, const uint32_t& aFlags,
     const OriginAttributes& aOriginAttributes, bool* aIsSecureURI) {
   nsCOMPtr<nsISiteSecurityService> sss(do_GetService(NS_SSSERVICE_CONTRACTID));
   if (!sss) {
     return IPC_FAIL_NO_REASON(this);
   }
-  nsCOMPtr<nsIURI> ourURI = DeserializeURI(aURI);
-  if (!ourURI) {
+  if (!aURI) {
     return IPC_FAIL_NO_REASON(this);
   }
-  nsresult rv = sss->IsSecureURI(aType, ourURI, aFlags, aOriginAttributes,
+  nsresult rv = sss->IsSecureURI(aType, aURI, aFlags, aOriginAttributes,
                                  nullptr, nullptr, aIsSecureURI);
   if (NS_FAILED(rv)) {
     return IPC_FAIL_NO_REASON(this);
@@ -3786,32 +3774,31 @@ mozilla::ipc::IPCResult ContentParent::RecvIsSecureURI(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvAccumulateMixedContentHSTS(
-    const URIParams& aURI, const bool& aActive,
+    nsIURI* aURI, const bool& aActive,
     const OriginAttributes& aOriginAttributes) {
-  nsCOMPtr<nsIURI> ourURI = DeserializeURI(aURI);
-  if (!ourURI) {
+  if (!aURI) {
     return IPC_FAIL_NO_REASON(this);
   }
-  nsMixedContentBlocker::AccumulateMixedContentHSTS(ourURI, aActive,
+  nsMixedContentBlocker::AccumulateMixedContentHSTS(aURI, aActive,
                                                     aOriginAttributes);
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvLoadURIExternal(
-    const URIParams& uri, PBrowserParent* windowContext) {
+    nsIURI* uri, PBrowserParent* windowContext) {
   nsCOMPtr<nsIExternalProtocolService> extProtService(
       do_GetService(NS_EXTERNALPROTOCOLSERVICE_CONTRACTID));
   if (!extProtService) {
     return IPC_OK();
   }
-  nsCOMPtr<nsIURI> ourURI = DeserializeURI(uri);
-  if (!ourURI) {
+
+  if (!uri) {
     return IPC_FAIL_NO_REASON(this);
   }
 
   RefPtr<RemoteWindowContext> context =
       new RemoteWindowContext(static_cast<BrowserParent*>(windowContext));
-  extProtService->LoadURI(ourURI, context);
+  extProtService->LoadURI(uri, context);
   return IPC_OK();
 }
 
@@ -4193,10 +4180,9 @@ nsresult ContentParent::DoSendAsyncMessage(JSContext* aCx,
 mozilla::ipc::IPCResult ContentParent::RecvKeywordToURI(
     const nsCString& aKeyword, const bool& aIsPrivateContext,
     nsString* aProviderName, RefPtr<nsIInputStream>* aPostData,
-    Maybe<URIParams>* aURI) {
+    RefPtr<nsIURI>* aURI) {
   *aPostData = nullptr;
-  *aURI = Nothing();
-
+  *aURI = nullptr;
   nsCOMPtr<nsIURIFixup> fixup = components::URIFixup::Service();
   if (!fixup) {
     return IPC_OK();
@@ -4210,10 +4196,9 @@ mozilla::ipc::IPCResult ContentParent::RecvKeywordToURI(
     return IPC_OK();
   }
   info->GetKeywordProviderName(*aProviderName);
-
   nsCOMPtr<nsIURI> uri;
   info->GetPreferredURI(getter_AddRefs(uri));
-  SerializeURI(uri, *aURI);
+  *aURI = uri;
   return IPC_OK();
 }
 
@@ -4238,18 +4223,16 @@ mozilla::ipc::IPCResult ContentParent::RecvNotifyKeywordSearchLoading(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvCopyFavicon(
-    const URIParams& aOldURI, const URIParams& aNewURI,
-    const IPC::Principal& aLoadingPrincipal, const bool& aInPrivateBrowsing) {
-  nsCOMPtr<nsIURI> oldURI = DeserializeURI(aOldURI);
-  if (!oldURI) {
-    return IPC_OK();
+    nsIURI* aOldURI, nsIURI* aNewURI, const IPC::Principal& aLoadingPrincipal,
+    const bool& aInPrivateBrowsing) {
+  if (!aOldURI) {
+    return IPC_FAIL(this, "aOldURI should not be null");
   }
-  nsCOMPtr<nsIURI> newURI = DeserializeURI(aNewURI);
-  if (!newURI) {
-    return IPC_OK();
+  if (!aNewURI) {
+    return IPC_FAIL(this, "aNewURI should not be null");
   }
 
-  nsDocShell::CopyFavicon(oldURI, newURI, aLoadingPrincipal,
+  nsDocShell::CopyFavicon(aOldURI, aNewURI, aLoadingPrincipal,
                           aInPrivateBrowsing);
   return IPC_OK();
 }
@@ -4465,7 +4448,7 @@ void ContentParent::NotifyRebuildFontList() {
 
 already_AddRefed<mozilla::docshell::POfflineCacheUpdateParent>
 ContentParent::AllocPOfflineCacheUpdateParent(
-    const URIParams& aManifestURI, const URIParams& aDocumentURI,
+    nsIURI* aManifestURI, nsIURI* aDocumentURI,
     const PrincipalInfo& aLoadingPrincipalInfo, const bool& aStickDocument,
     const CookieJarSettingsArgs& aCookieJarSettingsArgs) {
   RefPtr<mozilla::docshell::OfflineCacheUpdateParent> update =
@@ -4474,8 +4457,8 @@ ContentParent::AllocPOfflineCacheUpdateParent(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvPOfflineCacheUpdateConstructor(
-    POfflineCacheUpdateParent* aActor, const URIParams& aManifestURI,
-    const URIParams& aDocumentURI, const PrincipalInfo& aLoadingPrincipal,
+    POfflineCacheUpdateParent* aActor, nsIURI* aManifestURI,
+    nsIURI* aDocumentURI, const PrincipalInfo& aLoadingPrincipal,
     const bool& aStickDocument,
     const CookieJarSettingsArgs& aCookieJarSettingsArgs) {
   MOZ_ASSERT(aActor);
@@ -4842,10 +4825,10 @@ mozilla::ipc::IPCResult ContentParent::CommonCreateWindow(
 mozilla::ipc::IPCResult ContentParent::RecvCreateWindow(
     PBrowserParent* aThisTab, PBrowserParent* aNewTab,
     const uint32_t& aChromeFlags, const bool& aCalledFromJS,
-    const bool& aWidthSpecified, const Maybe<URIParams>& aURIToLoad,
-    const nsCString& aFeatures, const float& aFullZoom,
-    const IPC::Principal& aTriggeringPrincipal, nsIContentSecurityPolicy* aCsp,
-    nsIReferrerInfo* aReferrerInfo, CreateWindowResolver&& aResolve) {
+    const bool& aWidthSpecified, nsIURI* aURIToLoad, const nsCString& aFeatures,
+    const float& aFullZoom, const IPC::Principal& aTriggeringPrincipal,
+    nsIContentSecurityPolicy* aCsp, nsIReferrerInfo* aReferrerInfo,
+    CreateWindowResolver&& aResolve) {
   nsresult rv = NS_OK;
   CreatedWindowInfo cwi;
 
@@ -4878,13 +4861,11 @@ mozilla::ipc::IPCResult ContentParent::RecvCreateWindow(
   const uint64_t nextRemoteTabId = ++sNextRemoteTabId;
   sNextBrowserParents.Put(nextRemoteTabId, newTab);
 
-  const nsCOMPtr<nsIURI> uriToLoad = DeserializeURI(aURIToLoad);
-
   nsCOMPtr<nsIRemoteTab> newRemoteTab;
   int32_t openLocation = nsIBrowserDOMWindow::OPEN_NEWWINDOW;
   mozilla::ipc::IPCResult ipcResult = CommonCreateWindow(
       aThisTab, /* aSetOpener = */ true, aChromeFlags, aCalledFromJS,
-      aWidthSpecified, uriToLoad, aFeatures, aFullZoom, nextRemoteTabId,
+      aWidthSpecified, aURIToLoad, aFeatures, aFullZoom, nextRemoteTabId,
       VoidString(), rv, newRemoteTab, &cwi.windowOpened(), openLocation,
       aTriggeringPrincipal, aReferrerInfo,
       /* aLoadUri = */ false, aCsp);
@@ -4918,21 +4899,19 @@ mozilla::ipc::IPCResult ContentParent::RecvCreateWindow(
 
 mozilla::ipc::IPCResult ContentParent::RecvCreateWindowInDifferentProcess(
     PBrowserParent* aThisTab, const uint32_t& aChromeFlags,
-    const bool& aCalledFromJS, const bool& aWidthSpecified,
-    const Maybe<URIParams>& aURIToLoad, const nsCString& aFeatures,
-    const float& aFullZoom, const nsString& aName,
+    const bool& aCalledFromJS, const bool& aWidthSpecified, nsIURI* aURIToLoad,
+    const nsCString& aFeatures, const float& aFullZoom, const nsString& aName,
     nsIPrincipal* aTriggeringPrincipal, nsIContentSecurityPolicy* aCsp,
     nsIReferrerInfo* aReferrerInfo) {
   MOZ_DIAGNOSTIC_ASSERT(!nsContentUtils::IsSpecialName(aName));
 
   nsCOMPtr<nsIRemoteTab> newRemoteTab;
   bool windowIsNew;
-  nsCOMPtr<nsIURI> uriToLoad = DeserializeURI(aURIToLoad);
   int32_t openLocation = nsIBrowserDOMWindow::OPEN_NEWWINDOW;
 
   // If we have enough data, check the schemes of the loader and loadee
   // to make sure they make sense.
-  if (uriToLoad && uriToLoad->SchemeIs("file") &&
+  if (aURIToLoad && aURIToLoad->SchemeIs("file") &&
       !GetRemoteType().EqualsLiteral(FILE_REMOTE_TYPE) &&
       Preferences::GetBool("browser.tabs.remote.enforceRemoteTypeRestrictions",
                            false)) {
@@ -4940,7 +4919,7 @@ mozilla::ipc::IPCResult ContentParent::RecvCreateWindowInDifferentProcess(
 #  ifdef DEBUG
     nsAutoCString uriToLoadStr;
     nsAutoCString triggeringUriStr;
-    uriToLoad->GetAsciiSpec(uriToLoadStr);
+    aURIToLoad->GetAsciiSpec(uriToLoadStr);
     aTriggeringPrincipal->GetAsciiSpec(triggeringUriStr);
 
     NS_WARNING(nsPrintfCString(
@@ -4958,7 +4937,7 @@ mozilla::ipc::IPCResult ContentParent::RecvCreateWindowInDifferentProcess(
   nsresult rv;
   mozilla::ipc::IPCResult ipcResult = CommonCreateWindow(
       aThisTab, /* aSetOpener = */ false, aChromeFlags, aCalledFromJS,
-      aWidthSpecified, uriToLoad, aFeatures, aFullZoom,
+      aWidthSpecified, aURIToLoad, aFeatures, aFullZoom,
       /* aNextRemoteTabId = */ 0, aName, rv, newRemoteTab, &windowIsNew,
       openLocation, aTriggeringPrincipal, aReferrerInfo,
       /* aLoadUri = */ true, aCsp);
@@ -5033,14 +5012,13 @@ mozilla::ipc::IPCResult ContentParent::RecvSetupFamilyCharMap(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvGetHyphDict(
-    const mozilla::ipc::URIParams& aURI,
-    mozilla::ipc::SharedMemoryBasic::Handle* aOutHandle, uint32_t* aOutSize) {
-  nsCOMPtr<nsIURI> uri = DeserializeURI(aURI);
-  if (!uri) {
+    nsIURI* aURI, mozilla::ipc::SharedMemoryBasic::Handle* aOutHandle,
+    uint32_t* aOutSize) {
+  if (!aURI) {
     return IPC_FAIL_NO_REASON(this);
   }
   nsHyphenationManager::Instance()->ShareHyphDictToProcess(
-      uri, Pid(), aOutHandle, aOutSize);
+      aURI, Pid(), aOutHandle, aOutSize);
   return IPC_OK();
 }
 
@@ -5587,7 +5565,7 @@ bool ContentParent::DeallocPURLClassifierParent(PURLClassifierParent* aActor) {
 // PURLClassifierLocalParent
 
 PURLClassifierLocalParent* ContentParent::AllocPURLClassifierLocalParent(
-    const URIParams& aURI, const nsTArray<IPCURLClassifierFeature>& aFeatures) {
+    nsIURI* aURI, const nsTArray<IPCURLClassifierFeature>& aFeatures) {
   MOZ_ASSERT(NS_IsMainThread());
 
   RefPtr<URLClassifierLocalParent> actor = new URLClassifierLocalParent();
@@ -5595,21 +5573,20 @@ PURLClassifierLocalParent* ContentParent::AllocPURLClassifierLocalParent(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvPURLClassifierLocalConstructor(
-    PURLClassifierLocalParent* aActor, const URIParams& aURI,
+    PURLClassifierLocalParent* aActor, nsIURI* aURI,
     nsTArray<IPCURLClassifierFeature>&& aFeatures) {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(aActor);
 
   nsTArray<IPCURLClassifierFeature> features = std::move(aFeatures);
 
-  nsCOMPtr<nsIURI> uri = DeserializeURI(aURI);
-  if (!uri) {
-    NS_WARNING("Failed to DeserializeURI");
+  if (!aURI) {
+    NS_WARNING("aURI should not be null");
     return IPC_FAIL_NO_REASON(this);
   }
 
   auto* actor = static_cast<URLClassifierLocalParent*>(aActor);
-  return actor->StartClassify(uri, features);
+  return actor->StartClassify(aURI, features);
 }
 
 bool ContentParent::DeallocPURLClassifierLocalParent(
@@ -5623,7 +5600,7 @@ bool ContentParent::DeallocPURLClassifierLocalParent(
 }
 
 PLoginReputationParent* ContentParent::AllocPLoginReputationParent(
-    const URIParams& aURI) {
+    nsIURI* aURI) {
   MOZ_ASSERT(NS_IsMainThread());
 
   RefPtr<LoginReputationParent> actor = new LoginReputationParent();
@@ -5631,17 +5608,16 @@ PLoginReputationParent* ContentParent::AllocPLoginReputationParent(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvPLoginReputationConstructor(
-    PLoginReputationParent* aActor, const URIParams& aURI) {
+    PLoginReputationParent* aActor, nsIURI* aURI) {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(aActor);
 
-  nsCOMPtr<nsIURI> uri = DeserializeURI(aURI);
-  if (!uri) {
+  if (!aURI) {
     return IPC_FAIL_NO_REASON(this);
   }
 
   auto* actor = static_cast<LoginReputationParent*>(aActor);
-  return actor->QueryReputation(uri);
+  return actor->QueryReputation(aURI);
 }
 
 bool ContentParent::DeallocPLoginReputationParent(
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index c1c6bd80f6f2..04183943dd76 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -94,7 +94,6 @@ class PrintingParent;
 namespace ipc {
 class CrashReporterHost;
 class PFileDescriptorSetParent;
-class URIParams;
 class TestShellParent;
 #ifdef FUZZING
 class ProtocolFuzzerHelper;
@@ -149,7 +148,6 @@ class ContentParent final
   typedef mozilla::ipc::GeckoChildProcessHost GeckoChildProcessHost;
   typedef mozilla::ipc::PFileDescriptorSetParent PFileDescriptorSetParent;
   typedef mozilla::ipc::TestShellParent TestShellParent;
-  typedef mozilla::ipc::URIParams URIParams;
   typedef mozilla::ipc::PrincipalInfo PrincipalInfo;
   typedef mozilla::dom::ClonedMessageData ClonedMessageData;
   typedef mozilla::dom::BrowsingContextGroup BrowsingContextGroup;
@@ -489,13 +487,13 @@ class ContentParent final
                                                   const ContentParentId& aCpId);
 
   already_AddRefed<POfflineCacheUpdateParent> AllocPOfflineCacheUpdateParent(
-      const URIParams& aManifestURI, const URIParams& aDocumentURI,
+      nsIURI* aManifestURI, nsIURI* aDocumentURI,
       const PrincipalInfo& aLoadingPrincipalInfo, const bool& aStickDocument,
       const CookieJarSettingsArgs& aCookieJarSettingsArgs);
 
   virtual mozilla::ipc::IPCResult RecvPOfflineCacheUpdateConstructor(
-      POfflineCacheUpdateParent* aActor, const URIParams& aManifestURI,
-      const URIParams& aDocumentURI, const PrincipalInfo& aLoadingPrincipal,
+      POfflineCacheUpdateParent* aActor, nsIURI* aManifestURI,
+      nsIURI* aDocumentURI, const PrincipalInfo& aLoadingPrincipal,
       const bool& stickDocument,
       const CookieJarSettingsArgs& aCookieJarSettingsArgs) override;
 
@@ -523,7 +521,7 @@ class ContentParent final
   mozilla::ipc::IPCResult RecvCreateWindow(
       PBrowserParent* aThisBrowserParent, PBrowserParent* aNewTab,
       const uint32_t& aChromeFlags, const bool& aCalledFromJS,
-      const bool& aWidthSpecified, const Maybe<URIParams>& aURIToLoad,
+      const bool& aWidthSpecified, nsIURI* aURIToLoad,
       const nsCString& aFeatures, const float& aFullZoom,
       const IPC::Principal& aTriggeringPrincipal,
       nsIContentSecurityPolicy* aCsp, nsIReferrerInfo* aReferrerInfo,
@@ -532,7 +530,7 @@ class ContentParent final
   mozilla::ipc::IPCResult RecvCreateWindowInDifferentProcess(
       PBrowserParent* aThisTab, const uint32_t& aChromeFlags,
       const bool& aCalledFromJS, const bool& aWidthSpecified,
-      const Maybe<URIParams>& aURIToLoad, const nsCString& aFeatures,
+      nsIURI* aURIToLoad, const nsCString& aFeatures,
       const float& aFullZoom, const nsString& aName,
       nsIPrincipal* aTriggeringPrincipal, nsIContentSecurityPolicy* aCsp,
       nsIReferrerInfo* aReferrerInfo);
@@ -567,17 +565,16 @@ class ContentParent final
 
   // PURLClassifierLocalParent.
   PURLClassifierLocalParent* AllocPURLClassifierLocalParent(
-      const URIParams& aURI,
-      const nsTArray<IPCURLClassifierFeature>& aFeatures);
+      nsIURI* aURI, const nsTArray<IPCURLClassifierFeature>& aFeatures);
 
   virtual mozilla::ipc::IPCResult RecvPURLClassifierLocalConstructor(
-      PURLClassifierLocalParent* aActor, const URIParams& aURI,
+      PURLClassifierLocalParent* aActor, nsIURI* aURI,
       nsTArray<IPCURLClassifierFeature>&& aFeatures) override;
 
-  PLoginReputationParent* AllocPLoginReputationParent(const URIParams& aURI);
+  PLoginReputationParent* AllocPLoginReputationParent(nsIURI* aURI);
 
   virtual mozilla::ipc::IPCResult RecvPLoginReputationConstructor(
-      PLoginReputationParent* aActor, const URIParams& aURI) override;
+      PLoginReputationParent* aActor, nsIURI* aURI) override;
 
   bool DeallocPLoginReputationParent(PLoginReputationParent* aActor);
 
@@ -891,11 +888,11 @@ class ContentParent final
       const uint32_t& chromeFlags);
 
   mozilla::ipc::IPCResult RecvIsSecureURI(
-      const uint32_t& aType, const URIParams& aURI, const uint32_t& aFlags,
+      const uint32_t& aType, nsIURI* aURI, const uint32_t& aFlags,
       const OriginAttributes& aOriginAttributes, bool* aIsSecureURI);
 
   mozilla::ipc::IPCResult RecvAccumulateMixedContentHSTS(
-      const URIParams& aURI, const bool& aActive,
+      nsIURI* aURI, const bool& aActive,
       const OriginAttributes& aOriginAttributes);
 
   bool DeallocPHalParent(PHalParent*);
@@ -921,25 +918,22 @@ class ContentParent final
   bool DeallocPNeckoParent(PNeckoParent* necko);
 
   already_AddRefed<PExternalHelperAppParent> AllocPExternalHelperAppParent(
-      const Maybe<URIParams>& aUri,
-      const Maybe<mozilla::net::LoadInfoArgs>& aLoadInfoArgs,
+      nsIURI* aUri, const Maybe<mozilla::net::LoadInfoArgs>& aLoadInfoArgs,
       const nsCString& aMimeContentType, const nsCString& aContentDisposition,
       const uint32_t& aContentDispositionHint,
       const nsString& aContentDispositionFilename, const bool& aForceSave,
       const int64_t& aContentLength, const bool& aWasFileChannel,
-      const Maybe<URIParams>& aReferrer,
-      const MaybeDiscarded<BrowsingContext>& aContext,
+      nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
       const bool& aShouldCloseWindow);
 
   mozilla::ipc::IPCResult RecvPExternalHelperAppConstructor(
-      PExternalHelperAppParent* actor, const Maybe<URIParams>& uri,
+      PExternalHelperAppParent* actor, nsIURI* uri,
       const Maybe<LoadInfoArgs>& loadInfoArgs,
       const nsCString& aMimeContentType, const nsCString& aContentDisposition,
       const uint32_t& aContentDispositionHint,
       const nsString& aContentDispositionFilename, const bool& aForceSave,
       const int64_t& aContentLength, const bool& aWasFileChannel,
-      const Maybe<URIParams>& aReferrer,
-      const MaybeDiscarded<BrowsingContext>& aContext,
+      nsIURI* aReferrer, const MaybeDiscarded<BrowsingContext>& aContext,
       const bool& aShouldCloseWindow) override;
 
   already_AddRefed<PHandlerServiceParent> AllocPHandlerServiceParent();
@@ -994,7 +988,7 @@ class ContentParent final
       const int32_t& aWhichClipboard, const bool& aPlainTextOnly,
       nsTArray<nsCString>* aTypes);
 
-  mozilla::ipc::IPCResult RecvPlaySound(const URIParams& aURI);
+  mozilla::ipc::IPCResult RecvPlaySound(nsIURI* aURI);
   mozilla::ipc::IPCResult RecvBeep();
   mozilla::ipc::IPCResult RecvPlayEventSound(const uint32_t& aEventId);
 
@@ -1004,10 +998,10 @@ class ContentParent final
 
   mozilla::ipc::IPCResult RecvGetShowPasswordSetting(bool* showPassword);
 
-  mozilla::ipc::IPCResult RecvStartVisitedQueries(const nsTArray<URIParams>&);
+  mozilla::ipc::IPCResult RecvStartVisitedQueries(
+      const nsTArray<RefPtr<nsIURI>>&);
 
-  mozilla::ipc::IPCResult RecvSetURITitle(const URIParams& uri,
-                                          const nsString& title);
+  mozilla::ipc::IPCResult RecvSetURITitle(nsIURI* uri, const nsString& title);
 
   bool HasNotificationPermission(const IPC::Principal& aPrincipal);
 
@@ -1025,7 +1019,7 @@ class ContentParent final
   mozilla::ipc::IPCResult RecvNotificationEvent(
       const nsString& aType, const NotificationEventData& aData);
 
-  mozilla::ipc::IPCResult RecvLoadURIExternal(const URIParams& uri,
+  mozilla::ipc::IPCResult RecvLoadURIExternal(nsIURI* uri,
                                               PBrowserParent* windowContext);
   mozilla::ipc::IPCResult RecvExtProtocolChannelConnectParent(
       const uint32_t& registrarId);
@@ -1101,14 +1095,14 @@ class ContentParent final
                                            const bool& aIsPrivateContext,
                                            nsString* aProviderName,
                                            RefPtr<nsIInputStream>* aPostData,
-                                           Maybe<URIParams>* aURI);
+                                           RefPtr<nsIURI>* aURI);
 
   mozilla::ipc::IPCResult RecvNotifyKeywordSearchLoading(
       const nsString& aProvider, const nsString& aKeyword);
 
   mozilla::ipc::IPCResult RecvCopyFavicon(
-      const URIParams& aOldURI, const URIParams& aNewURI,
-      const IPC::Principal& aLoadingPrincipal, const bool& aInPrivateBrowsing);
+      nsIURI* aOldURI, nsIURI* aNewURI, const IPC::Principal& aLoadingPrincipal,
+      const bool& aInPrivateBrowsing);
 
   virtual void ProcessingError(Result aCode, const char* aMsgName) override;
 
@@ -1170,8 +1164,8 @@ class ContentParent final
       const mozilla::fontlist::Pointer& aFamilyPtr);
 
   mozilla::ipc::IPCResult RecvGetHyphDict(
-      const mozilla::ipc::URIParams& aURIParams,
-      mozilla::ipc::SharedMemoryBasic::Handle* aOutHandle, uint32_t* aOutSize);
+      nsIURI* aURIParams, mozilla::ipc::SharedMemoryBasic::Handle* aOutHandle,
+      uint32_t* aOutSize);
 
   mozilla::ipc::IPCResult RecvNotifyBenchmarkResult(const nsString& aCodecName,
                                                     const uint32_t& aDecodeFPS);
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 5cac8e4b05aa..4bbb5e44ee04 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -54,7 +54,6 @@ include JavaScriptTypes;
 include IPCBlob;
 include IPCStream;
 include PTabContext;
-include URIParams;
 include PluginTypes;
 include ProtocolTypes;
 include PBackgroundSharedTypes;
@@ -191,10 +190,10 @@ union FileDescOrError {
 struct DomainPolicyClone
 {
     bool        active;
-    URIParams[] blocklist;
-    URIParams[] allowlist;
-    URIParams[] superBlocklist;
-    URIParams[] superAllowlist;
+    nsIURI[] blocklist;
+    nsIURI[] allowlist;
+    nsIURI[] superBlocklist;
+    nsIURI[] superAllowlist;
 };
 
 struct AndroidSystemInfo
@@ -282,7 +281,7 @@ struct XPCOMInitData
     nsString[] dictionaries;
     ClipboardCapabilities clipboardCaps;
     DomainPolicyClone domainPolicy;
-    URIParams? userContentSheetURL;
+    nsIURI userContentSheetURL;
     GfxVarUpdate[] gfxNonDefaultVarUpdates;
     ContentDeviceData contentDeviceData;
     GfxInfoFeatureStatus[] gfxFeatureStatus;
@@ -294,7 +293,7 @@ struct XPCOMInitData
 
 struct VisitedQueryResult
 {
-    URIParams uri;
+    nsIURI uri;
     bool visited;
 };
 
@@ -634,8 +633,8 @@ child:
     /**
      * Used to manage nsIStyleSheetService across processes.
      */
-    async LoadAndRegisterSheet(URIParams uri, uint32_t type);
-    async UnregisterSheet(URIParams uri, uint32_t type);
+    async LoadAndRegisterSheet(nsIURI uri, uint32_t type);
+    async UnregisterSheet(nsIURI uri, uint32_t type);
 
     /**
      * Notify idle observers in the child
@@ -648,7 +647,7 @@ child:
                          LayoutDeviceIntPoint aDragEndPoint,
                          uint32_t aKeyModifiers);
 
-    async DomainSetChanged(uint32_t aSetType, uint32_t aChangeType, URIParams? aDomain);
+    async DomainSetChanged(uint32_t aSetType, uint32_t aChangeType, nsIURI aDomain);
 
     /**
      * Notify the child to shutdown. The child will in turn call FinishShutdown
@@ -891,11 +890,11 @@ parent:
 
     async InitCrashReporter(Shmem shmem, NativeThreadId tid);
 
-    sync IsSecureURI(uint32_t aType, URIParams aURI, uint32_t aFlags,
+    sync IsSecureURI(uint32_t aType, nsIURI aURI, uint32_t aFlags,
                      OriginAttributes aOriginAttributes)
         returns (bool isSecureURI);
 
-    async AccumulateMixedContentHSTS(URIParams aURI, bool aActive,
+    async AccumulateMixedContentHSTS(nsIURI aURI, bool aActive,
                                      OriginAttributes aOriginAttributes);
 
     nested(inside_cpow) async PHal();
@@ -923,9 +922,9 @@ parent:
     sync PURLClassifier(Principal principal)
         returns (bool success);
 
-    async PURLClassifierLocal(URIParams uri, IPCURLClassifierFeature[] features);
+    async PURLClassifierLocal(nsIURI uri, IPCURLClassifierFeature[] features);
 
-    async PLoginReputation(URIParams formURI);
+    async PLoginReputation(nsIURI formURI);
 
     async PSessionStorageObserver();
 
@@ -938,10 +937,10 @@ parent:
 
     // Services remoting
 
-    async StartVisitedQueries(URIParams[] uri);
-    async SetURITitle(URIParams uri, nsString title);
+    async StartVisitedQueries(nsIURI[] uri);
+    async SetURITitle(nsIURI uri, nsString title);
 
-    async LoadURIExternal(URIParams uri, PBrowser windowContext);
+    async LoadURIExternal(nsIURI uri, PBrowser windowContext);
     async ExtProtocolChannelConnectParent(uint32_t registrarId);
 
     // PrefService message
@@ -997,7 +996,7 @@ parent:
     // nsIMIMEInfo and other such influences.
     // Pass true for aShouldCloseWindow to specify that aContext was opened specifically
     // for this load, and should be closed once we've handled it.
-    async PExternalHelperApp(URIParams? uri,
+    async PExternalHelperApp(nsIURI uri,
                              LoadInfoArgs? loadInfoArgs,
                              nsCString aMimeContentType,
                              nsCString aContentDisposition,
@@ -1006,7 +1005,7 @@ parent:
                              bool aForceSave,
                              int64_t aContentLength,
                              bool aWasFileChannel,
-                             URIParams? aReferrer,
+                             nsIURI aReferrer,
                              MaybeDiscardedBrowsingContext aContext,
                              bool aShouldCloseWindow);
 
@@ -1046,7 +1045,7 @@ parent:
 
     // 'Play', 'Beep' and 'PlayEventSound' are the only nsISound methods used in
     // the content process.
-    async PlaySound(URIParams aURL) compress;
+    async PlaySound(nsIURI aURL) compress;
     async Beep() compress;
     async PlayEventSound(uint32_t aEventId) compress;
 
@@ -1065,11 +1064,11 @@ parent:
     async DeviceReset();
 
     sync KeywordToURI(nsCString keyword, bool isPrivateContext)
-        returns (nsString providerName, nsIInputStream postData, URIParams? uri);
+        returns (nsString providerName, nsIInputStream postData, nsIURI uri);
 
     sync NotifyKeywordSearchLoading(nsString providerName, nsString keyword);
 
-    async CopyFavicon(URIParams oldURI, URIParams newURI, Principal aLoadingPrincipal, bool isPrivate);
+    async CopyFavicon(nsIURI oldURI, nsIURI newURI, Principal aLoadingPrincipal, bool isPrivate);
 
     /**
      * Notifies the parent about a recording device is starting or shutdown.
@@ -1134,7 +1133,7 @@ parent:
      * @param tabId
      *   To identify which tab owns the app.
      */
-    async POfflineCacheUpdate(URIParams manifestURI, URIParams documentURI,
+    async POfflineCacheUpdate(nsIURI manifestURI, nsIURI documentURI,
                               PrincipalInfo loadingPrincipal, bool stickDocument,
                               CookieJarSettingsArgs cookieJarSettings);
 
@@ -1348,14 +1347,14 @@ parent:
      * @param aLoaded
      *   Returns the size in bytes of the resource.
      */
-    sync GetHyphDict(URIParams aURI) returns (Handle aHandle, uint32_t aSize);
+    sync GetHyphDict(nsIURI aURI) returns (Handle aHandle, uint32_t aSize);
 
     async CreateWindow(nullable PBrowser aThisTab,
                        PBrowser aNewTab,
                        uint32_t aChromeFlags,
                        bool aCalledFromJS,
                        bool aWidthSpecified,
-                       URIParams? aURIToLoad,
+                       nsIURI aURIToLoad,
                        nsCString aFeatures,
                        float aFullZoom,
                        Principal aTriggeringPrincipal,
@@ -1368,7 +1367,7 @@ parent:
       uint32_t aChromeFlags,
       bool aCalledFromJS,
       bool aWidthSpecified,
-      URIParams? aURIToLoad,
+      nsIURI aURIToLoad,
       nsCString aFeatures,
       float aFullZoom,
       nsString aName,
diff --git a/dom/security/nsMixedContentBlocker.cpp b/dom/security/nsMixedContentBlocker.cpp
index bfe6a2acc98e..ab757b193d49 100644
--- a/dom/security/nsMixedContentBlocker.cpp
+++ b/dom/security/nsMixedContentBlocker.cpp
@@ -986,9 +986,8 @@ nsresult nsMixedContentBlocker::ShouldLoad(
       mozilla::dom::ContentChild* cc =
           mozilla::dom::ContentChild::GetSingleton();
       if (cc) {
-        mozilla::ipc::URIParams uri;
-        SerializeURI(innerContentLocation, uri);
-        cc->SendAccumulateMixedContentHSTS(uri, active, originAttributes);
+        cc->SendAccumulateMixedContentHSTS(innerContentLocation, active,
+                                           originAttributes);
       }
     }
   }
diff --git a/intl/hyphenation/glue/nsHyphenator.cpp b/intl/hyphenation/glue/nsHyphenator.cpp
index 01a5225b290e..065a1afe17b8 100644
--- a/intl/hyphenation/glue/nsHyphenator.cpp
+++ b/intl/hyphenation/glue/nsHyphenator.cpp
@@ -64,9 +64,8 @@ already_AddRefed<ipc::SharedMemoryBasic> GetHyphDictFromParent(
   MOZ_ASSERT(!XRE_IsParentProcess());
   ipc::SharedMemoryBasic::Handle handle = ipc::SharedMemoryBasic::NULLHandle();
   uint32_t size;
-  ipc::URIParams params;
-  SerializeURI(aURI, params);
-  if (!dom::ContentChild::GetSingleton()->SendGetHyphDict(params, &handle,
+  MOZ_ASSERT(aURI);
+  if (!dom::ContentChild::GetSingleton()->SendGetHyphDict(aURI, &handle,
                                                           &size)) {
     return nullptr;
   }
diff --git a/layout/base/nsStyleSheetService.cpp b/layout/base/nsStyleSheetService.cpp
index 45fbd47e71d7..b025d9438444 100644
--- a/layout/base/nsStyleSheetService.cpp
+++ b/layout/base/nsStyleSheetService.cpp
@@ -169,11 +169,8 @@ nsStyleSheetService::LoadAndRegisterSheet(nsIURI* aSheetURI,
         return rv;
       }
 
-      mozilla::ipc::URIParams uri;
-      SerializeURI(aSheetURI, uri);
-
       for (uint32_t i = 0; i < children.Length(); i++) {
-        Unused << children[i]->SendLoadAndRegisterSheet(uri, aSheetType);
+        Unused << children[i]->SendLoadAndRegisterSheet(aSheetURI, aSheetType);
       }
     }
   }
@@ -327,11 +324,8 @@ nsStyleSheetService::UnregisterSheet(nsIURI* aSheetURI, uint32_t aSheetType) {
       return NS_OK;
     }
 
-    mozilla::ipc::URIParams uri;
-    SerializeURI(aSheetURI, uri);
-
     for (uint32_t i = 0; i < children.Length(); i++) {
-      Unused << children[i]->SendUnregisterSheet(uri, aSheetType);
+      Unused << children[i]->SendUnregisterSheet(aSheetURI, aSheetType);
     }
   }
 
diff --git a/toolkit/components/places/History.cpp b/toolkit/components/places/History.cpp
index d3d2ec5d1db3..ef3cc3e4ce18 100644
--- a/toolkit/components/places/History.cpp
+++ b/toolkit/components/places/History.cpp
@@ -436,7 +436,7 @@ class VisitedQuery final : public AsyncStatementCallback {
         AutoTArray<VisitedQueryResult, 1> results;
         VisitedQueryResult& result = *results.AppendElement();
         result.visited() = mIsVisited;
-        SerializeURI(mURI, result.uri());
+        result.uri() = mURI;
         history->NotifyVisitedParent(results);
       }
     }
@@ -584,7 +584,7 @@ class NotifyManyVisitsObservers : public Runnable {
 
         if (BrowserTabsRemoteAutostart()) {
           VisitedQueryResult& result = *results.AppendElement();
-          SerializeURI(uris[i], result.uri());
+          result.uri() = uris[i];
           result.visited() = true;
         }
       }
@@ -596,7 +596,7 @@ class NotifyManyVisitsObservers : public Runnable {
 
       if (BrowserTabsRemoteAutostart()) {
         VisitedQueryResult& result = *results.AppendElement();
-        SerializeURI(uris[0], result.uri());
+        result.uri() = uris[0];
         result.visited() = true;
         mHistory->NotifyVisitedParent(results);
       }
@@ -1993,12 +1993,9 @@ History::SetURITitle(nsIURI* aURI, const nsAString& aTitle) {
   }
 
   if (XRE_IsContentProcess()) {
-    URIParams uri;
-    SerializeURI(aURI, uri);
-
     auto* cpc = dom::ContentChild::GetSingleton();
     MOZ_ASSERT(cpc, "Content Protocol is NULL!");
-    Unused << cpc->SendSetURITitle(uri, PromiseFlatString(aTitle));
+    Unused << cpc->SendSetURITitle(aURI, PromiseFlatString(aTitle));
     return NS_OK;
   }
 
@@ -2206,9 +2203,9 @@ History::IsURIVisited(nsIURI* aURI, mozIVisitedStatusCallback* aCallback) {
 void History::StartPendingVisitedQueries(
     const PendingVisitedQueries& aQueries) {
   if (XRE_IsContentProcess()) {
-    nsTArray<URIParams> uris(aQueries.Count());
+    nsTArray<RefPtr<nsIURI>> uris(aQueries.Count());
     for (auto iter = aQueries.ConstIter(); !iter.Done(); iter.Next()) {
-      SerializeURI(iter.Get()->GetKey(), *uris.AppendElement());
+      uris.AppendElement(iter.Get()->GetKey());
     }
     auto* cpc = mozilla::dom::ContentChild::GetSingleton();
     MOZ_ASSERT(cpc, "Content Protocol is NULL!");
diff --git a/toolkit/components/reputationservice/LoginReputation.cpp b/toolkit/components/reputationservice/LoginReputation.cpp
index 1c32a9e8ddab..367b9e2e60bd 100644
--- a/toolkit/components/reputationservice/LoginReputation.cpp
+++ b/toolkit/components/reputationservice/LoginReputation.cpp
@@ -298,10 +298,7 @@ LoginReputationService::QueryReputationAsync(
       return NS_ERROR_FAILURE;
     }
 
-    URIParams uri;
-    SerializeURI(documentURI, uri);
-
-    if (!content->SendPLoginReputationConstructor(uri)) {
+    if (!content->SendPLoginReputationConstructor(documentURI)) {
       return NS_ERROR_FAILURE;
     }
   } else {
diff --git a/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp b/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
index 8418dc2e32b7..63e7b528f90f 100644
--- a/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
+++ b/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
@@ -2446,9 +2446,6 @@ nsUrlClassifierDBService::AsyncClassifyLocalWithFeatures(
         mozilla::SystemGroup::EventTargetFor(mozilla::TaskCategory::Other);
     content->SetEventTargetForActor(actor, systemGroupEventTarget);
 
-    URIParams uri;
-    SerializeURI(aURI, uri);
-
     nsTArray<IPCURLClassifierFeature> ipcFeatures;
     for (nsIUrlClassifierFeature* feature : aFeatures) {
       nsAutoCString name;
@@ -2473,7 +2470,8 @@ nsUrlClassifierDBService::AsyncClassifyLocalWithFeatures(
           IPCURLClassifierFeature(name, tables, skipHostList));
     }
 
-    if (!content->SendPURLClassifierLocalConstructor(actor, uri, ipcFeatures)) {
+    if (!content->SendPURLClassifierLocalConstructor(actor, aURI,
+                                                     ipcFeatures)) {
       return NS_ERROR_FAILURE;
     }
 
diff --git a/uriloader/exthandler/ExternalHelperAppParent.cpp b/uriloader/exthandler/ExternalHelperAppParent.cpp
index 7ba2f7806e01..584d0f7e6271 100644
--- a/uriloader/exthandler/ExternalHelperAppParent.cpp
+++ b/uriloader/exthandler/ExternalHelperAppParent.cpp
@@ -34,11 +34,11 @@ NS_IMPL_ISUPPORTS_INHERITED(ExternalHelperAppParent, nsHashPropertyBag,
                             nsIStreamListener, nsIExternalHelperAppParent)
 
 ExternalHelperAppParent::ExternalHelperAppParent(
-    const Maybe<URIParams>& uri, const int64_t& aContentLength,
-    const bool& aWasFileChannel, const nsCString& aContentDispositionHeader,
+    nsIURI* uri, const int64_t& aContentLength, const bool& aWasFileChannel,
+    const nsCString& aContentDispositionHeader,
     const uint32_t& aContentDispositionHint,
     const nsString& aContentDispositionFilename)
-    : mURI(DeserializeURI(uri)),
+    : mURI(uri),
       mPending(false)
 #ifdef DEBUG
       ,
@@ -66,7 +66,7 @@ ExternalHelperAppParent::ExternalHelperAppParent(
 void ExternalHelperAppParent::Init(
     const Maybe<mozilla::net::LoadInfoArgs>& aLoadInfoArgs,
     const nsCString& aMimeContentType, const bool& aForceSave,
-    const Maybe<URIParams>& aReferrer, BrowsingContext* aContext,
+    nsIURI* aReferrer, BrowsingContext* aContext,
     const bool& aShouldCloseWindow) {
   mozilla::ipc::LoadInfoArgsToLoadInfo(aLoadInfoArgs,
                                        getter_AddRefs(mLoadInfo));
@@ -75,10 +75,10 @@ void ExternalHelperAppParent::Init(
       do_GetService(NS_EXTERNALHELPERAPPSERVICE_CONTRACTID);
   NS_ASSERTION(helperAppService, "No Helper App Service!");
 
-  nsCOMPtr<nsIURI> referrer = DeserializeURI(aReferrer);
-  if (referrer)
+  if (aReferrer) {
     SetPropertyAsInterface(NS_LITERAL_STRING("docshell.internalReferrer"),
-                           referrer);
+                           aReferrer);
+  }
 
   if (aContext) {
     WindowGlobalParent* parent =
@@ -125,7 +125,9 @@ mozilla::ipc::IPCResult ExternalHelperAppParent::RecvOnStartRequest(
 
 mozilla::ipc::IPCResult ExternalHelperAppParent::RecvOnDataAvailable(
     const nsCString& data, const uint64_t& offset, const uint32_t& count) {
-  if (NS_FAILED(mStatus)) return IPC_OK();
+  if (NS_FAILED(mStatus)) {
+    return IPC_OK();
+  }
 
   MOZ_ASSERT(!mDiverted,
              "child forwarding callbacks after request was diverted");
@@ -391,7 +393,9 @@ ExternalHelperAppParent::SetContentDisposition(uint32_t aContentDisposition) {
 NS_IMETHODIMP
 ExternalHelperAppParent::GetContentDispositionFilename(
     nsAString& aContentDispositionFilename) {
-  if (mContentDispositionFilename.IsEmpty()) return NS_ERROR_NOT_AVAILABLE;
+  if (mContentDispositionFilename.IsEmpty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
 
   aContentDispositionFilename = mContentDispositionFilename;
   return NS_OK;
@@ -407,7 +411,9 @@ ExternalHelperAppParent::SetContentDispositionFilename(
 NS_IMETHODIMP
 ExternalHelperAppParent::GetContentDispositionHeader(
     nsACString& aContentDispositionHeader) {
-  if (mContentDispositionHeader.IsEmpty()) return NS_ERROR_NOT_AVAILABLE;
+  if (mContentDispositionHeader.IsEmpty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
 
   aContentDispositionHeader = mContentDispositionHeader;
   return NS_OK;
@@ -415,10 +421,11 @@ ExternalHelperAppParent::GetContentDispositionHeader(
 
 NS_IMETHODIMP
 ExternalHelperAppParent::GetContentLength(int64_t* aContentLength) {
-  if (mContentLength < 0)
+  if (mContentLength < 0) {
     *aContentLength = -1;
-  else
+  } else {
     *aContentLength = mContentLength;
+  }
   return NS_OK;
 }
 
diff --git a/uriloader/exthandler/ExternalHelperAppParent.h b/uriloader/exthandler/ExternalHelperAppParent.h
index 59006e6610fa..6ba053d29c6e 100644
--- a/uriloader/exthandler/ExternalHelperAppParent.h
+++ b/uriloader/exthandler/ExternalHelperAppParent.h
@@ -21,10 +21,6 @@ class nsExternalAppHandler;
 
 namespace mozilla {
 
-namespace ipc {
-class URIParams;
-}  // namespace ipc
-
 namespace net {
 class PChannelDiverterParent;
 }  // namespace net
@@ -84,16 +80,15 @@ class ExternalHelperAppParent
 
   bool WasFileChannel() override { return mWasFileChannel; }
 
-  ExternalHelperAppParent(const Maybe<mozilla::ipc::URIParams>& uri,
-                          const int64_t& contentLength,
+  ExternalHelperAppParent(nsIURI* uri, const int64_t& contentLength,
                           const bool& wasFileChannel,
                           const nsCString& aContentDispositionHeader,
                           const uint32_t& aContentDispositionHint,
                           const nsString& aContentDispositionFilename);
   void Init(const Maybe<mozilla::net::LoadInfoArgs>& aLoadInfoArgs,
             const nsCString& aMimeContentType, const bool& aForceSave,
-            const Maybe<mozilla::ipc::URIParams>& aReferrer,
-            BrowsingContext* aContext, const bool& aShouldCloseWindow);
+            nsIURI* aReferrer, BrowsingContext* aContext,
+            const bool& aShouldCloseWindow);
 
  protected:
   virtual ~ExternalHelperAppParent();
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index b1d5612ce21f..609d710cf6d2 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -623,10 +623,6 @@ nsresult nsExternalHelperAppService::DoContentContentProcessHelper(
   nsCOMPtr<nsIURI> referrer;
   NS_GetReferrerFromChannel(channel, getter_AddRefs(referrer));
 
-  Maybe<URIParams> uriParams, referrerParams;
-  SerializeURI(uri, uriParams);
-  SerializeURI(referrer, referrerParams);
-
   Maybe<mozilla::net::LoadInfoArgs> loadInfoArgs;
   MOZ_ALWAYS_SUCCEEDS(LoadInfoToLoadInfoArgs(loadInfo, &loadInfoArgs));
 
@@ -644,9 +640,9 @@ nsresult nsExternalHelperAppService::DoContentContentProcessHelper(
   // DoContent.
   RefPtr<ExternalHelperAppChild> childListener = new ExternalHelperAppChild();
   MOZ_ALWAYS_TRUE(child->SendPExternalHelperAppConstructor(
-      childListener, uriParams, loadInfoArgs, nsCString(aMimeContentType), disp,
+      childListener, uri, loadInfoArgs, nsCString(aMimeContentType), disp,
       contentDisposition, fileName, aForceSave, contentLength, wasFileChannel,
-      referrerParams, aContentContext, shouldCloseWindow));
+      referrer, aContentContext, shouldCloseWindow));
 
   NS_ADDREF(*aStreamListener = childListener);
 
@@ -929,12 +925,9 @@ nsExternalHelperAppService::LoadURI(nsIURI* aURI,
   NS_ENSURE_ARG_POINTER(aURI);
 
   if (XRE_IsContentProcess()) {
-    URIParams uri;
-    SerializeURI(aURI, uri);
-
     nsCOMPtr<nsIBrowserChild> browserChild(do_GetInterface(aWindowContext));
     mozilla::dom::ContentChild::GetSingleton()->SendLoadURIExternal(
-        uri, static_cast<dom::BrowserChild*>(browserChild.get()));
+        aURI, static_cast<dom::BrowserChild*>(browserChild.get()));
     return NS_OK;
   }
 
diff --git a/uriloader/prefetch/OfflineCacheUpdateChild.cpp b/uriloader/prefetch/OfflineCacheUpdateChild.cpp
index 3581b2495301..b29ab2ee38fb 100644
--- a/uriloader/prefetch/OfflineCacheUpdateChild.cpp
+++ b/uriloader/prefetch/OfflineCacheUpdateChild.cpp
@@ -366,10 +366,6 @@ OfflineCacheUpdateChild::Schedule() {
     return NS_ERROR_FAILURE;
   }
 
-  URIParams manifestURI, documentURI;
-  SerializeURI(mManifestURI, manifestURI);
-  SerializeURI(mDocumentURI, documentURI);
-
   nsresult rv = NS_OK;
   PrincipalInfo loadingPrincipalInfo;
   rv = PrincipalToPrincipalInfo(mLoadingPrincipal, &loadingPrincipalInfo);
@@ -398,7 +394,7 @@ OfflineCacheUpdateChild::Schedule() {
   }
 
   ContentChild::GetSingleton()->SendPOfflineCacheUpdateConstructor(
-      this, manifestURI, documentURI, loadingPrincipalInfo, stickDocument,
+      this, mManifestURI, mDocumentURI, loadingPrincipalInfo, stickDocument,
       csArgs);
 
   return NS_OK;
diff --git a/uriloader/prefetch/OfflineCacheUpdateParent.cpp b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
index f769a9c4215c..fa8e62a1316d 100644
--- a/uriloader/prefetch/OfflineCacheUpdateParent.cpp
+++ b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
@@ -70,7 +70,7 @@ void OfflineCacheUpdateParent::ActorDestroy(ActorDestroyReason why) {
 }
 
 nsresult OfflineCacheUpdateParent::Schedule(
-    const URIParams& aManifestURI, const URIParams& aDocumentURI,
+    nsIURI* aManifestURI, nsIURI* aDocumentURI,
     const PrincipalInfo& aLoadingPrincipalInfo, const bool& stickDocument,
     const CookieJarSettingsArgs& aCookieJarSettingsArgs) {
   LOG(("OfflineCacheUpdateParent::RecvSchedule [%p]", this));
@@ -78,41 +78,48 @@ nsresult OfflineCacheUpdateParent::Schedule(
   nsresult rv;
 
   RefPtr<nsOfflineCacheUpdate> update;
-  nsCOMPtr<nsIURI> manifestURI = DeserializeURI(aManifestURI);
-  if (!manifestURI) return NS_ERROR_FAILURE;
+  if (!aManifestURI) {
+    return NS_ERROR_FAILURE;
+  }
 
   mLoadingPrincipal = PrincipalInfoToPrincipal(aLoadingPrincipalInfo, &rv);
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsOfflineCacheUpdateService* service =
       nsOfflineCacheUpdateService::EnsureService();
-  if (!service) return NS_ERROR_FAILURE;
+  if (!service) {
+    return NS_ERROR_FAILURE;
+  }
 
   bool offlinePermissionAllowed = false;
 
   rv = service->OfflineAppAllowed(mLoadingPrincipal, &offlinePermissionAllowed);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (!offlinePermissionAllowed) return NS_ERROR_DOM_SECURITY_ERR;
-
-  nsCOMPtr<nsIURI> documentURI = DeserializeURI(aDocumentURI);
-  if (!documentURI) return NS_ERROR_FAILURE;
-
-  if (!NS_SecurityCompareURIs(manifestURI, documentURI, false))
+  if (!offlinePermissionAllowed) {
     return NS_ERROR_DOM_SECURITY_ERR;
+  }
+
+  if (!aDocumentURI) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!NS_SecurityCompareURIs(aManifestURI, aDocumentURI, false)) {
+    return NS_ERROR_DOM_SECURITY_ERR;
+  }
 
   nsAutoCString originSuffix;
   rv = mLoadingPrincipal->GetOriginSuffix(originSuffix);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  service->FindUpdate(manifestURI, originSuffix, nullptr,
+  service->FindUpdate(aManifestURI, originSuffix, nullptr,
                       getter_AddRefs(update));
   if (!update) {
     update = new nsOfflineCacheUpdate();
 
     // Leave aDocument argument null. Only glues and children keep
     // document instances.
-    rv = update->Init(manifestURI, documentURI, mLoadingPrincipal, nullptr,
+    rv = update->Init(aManifestURI, aDocumentURI, mLoadingPrincipal, nullptr,
                       nullptr);
     NS_ENSURE_SUCCESS(rv, rv);
 
@@ -129,7 +136,7 @@ nsresult OfflineCacheUpdateParent::Schedule(
   }
 
   if (stickDocument) {
-    update->StickDocument(documentURI);
+    update->StickDocument(aDocumentURI);
   }
 
   return NS_OK;
@@ -138,7 +145,9 @@ nsresult OfflineCacheUpdateParent::Schedule(
 NS_IMETHODIMP
 OfflineCacheUpdateParent::UpdateStateChanged(nsIOfflineCacheUpdate* aUpdate,
                                              uint32_t state) {
-  if (mIPCClosed) return NS_ERROR_UNEXPECTED;
+  if (mIPCClosed) {
+    return NS_ERROR_UNEXPECTED;
+  }
 
   LOG(("OfflineCacheUpdateParent::StateEvent [%p]", this));
 
@@ -164,7 +173,9 @@ OfflineCacheUpdateParent::UpdateStateChanged(nsIOfflineCacheUpdate* aUpdate,
 NS_IMETHODIMP
 OfflineCacheUpdateParent::ApplicationCacheAvailable(
     nsIApplicationCache* aApplicationCache) {
-  if (mIPCClosed) return NS_ERROR_UNEXPECTED;
+  if (mIPCClosed) {
+    return NS_ERROR_UNEXPECTED;
+  }
 
   NS_ENSURE_ARG(aApplicationCache);
 
diff --git a/uriloader/prefetch/OfflineCacheUpdateParent.h b/uriloader/prefetch/OfflineCacheUpdateParent.h
index 1e5e0ada98ef..b1bc3d90cc3c 100644
--- a/uriloader/prefetch/OfflineCacheUpdateParent.h
+++ b/uriloader/prefetch/OfflineCacheUpdateParent.h
@@ -39,7 +39,7 @@ class OfflineCacheUpdateParent : public POfflineCacheUpdateParent,
   NS_DECL_NSIOFFLINECACHEUPDATEOBSERVER
   NS_DECL_NSILOADCONTEXT
 
-  nsresult Schedule(const URIParams& manifestURI, const URIParams& documentURI,
+  nsresult Schedule(nsIURI* manifestURI, nsIURI* documentURI,
                     const PrincipalInfo& loadingPrincipalInfo,
                     const bool& stickDocument,
                     const net::CookieJarSettingsArgs& aCookieJarSettingsArgs);
diff --git a/widget/nsSoundProxy.cpp b/widget/nsSoundProxy.cpp
index bbd1234f1955..e991fa240ecf 100644
--- a/widget/nsSoundProxy.cpp
+++ b/widget/nsSoundProxy.cpp
@@ -16,16 +16,12 @@ NS_IMPL_ISUPPORTS(nsSoundProxy, nsISound)
 NS_IMETHODIMP
 nsSoundProxy::Play(nsIURL* aURL) {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Content);
-
-  nsCOMPtr<nsIURI> soundURI(aURL);
   // Only allow playing a chrome:// URL from the content process.
-  if (!soundURI || !soundURI->SchemeIs("chrome")) {
+  if (!aURL || !aURL->SchemeIs("chrome")) {
     return NS_ERROR_FAILURE;
   }
 
-  mozilla::ipc::URIParams soundParams;
-  mozilla::ipc::SerializeURI(soundURI, soundParams);
-  ContentChild::GetSingleton()->SendPlaySound(soundParams);
+  ContentChild::GetSingleton()->SendPlaySound(aURL);
   return NS_OK;
 }