diff --git a/dom/base/nsContentSink.cpp b/dom/base/nsContentSink.cpp
index 8210bc33de7d..521e4ac7d551 100644
--- a/dom/base/nsContentSink.cpp
+++ b/dom/base/nsContentSink.cpp
@@ -438,18 +438,17 @@ void nsContentSink::PreloadHref(const nsAString& aHref, const nsAString& aAs,
   }
 
   nsAttrValue asAttr;
-  HTMLLinkElement::ParseAsValue(aAs, asAttr);
+  mozilla::net::ParseAsValue(aAs, asAttr);
 
   nsAutoString mimeType;
   nsAutoString notUsed;
   nsContentUtils::SplitMimeType(aType, mimeType, notUsed);
 
-  auto policyType = HTMLLinkElement::AsValueToContentPolicy(asAttr);
+  auto policyType = mozilla::net::AsValueToContentPolicy(asAttr);
   if (policyType == nsIContentPolicy::TYPE_INVALID ||
-      !HTMLLinkElement::CheckPreloadAttrs(asAttr, mimeType, aMedia,
-                                          mDocument)) {
+      !mozilla::net::CheckPreloadAttrs(asAttr, mimeType, aMedia, mDocument)) {
     // Ignore preload wrong or empty attributes.
-    HTMLLinkElement::WarnIgnoredPreload(*mDocument, *uri);
+    mozilla::net::WarnIgnoredPreload(*mDocument, *uri);
     return;
   }
 
diff --git a/dom/html/HTMLLinkElement.cpp b/dom/html/HTMLLinkElement.cpp
index 18f127fef023..47e1634e800c 100644
--- a/dom/html/HTMLLinkElement.cpp
+++ b/dom/html/HTMLLinkElement.cpp
@@ -148,7 +148,7 @@ bool HTMLLinkElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
     }
 
     if (aAttribute == nsGkAtoms::as) {
-      ParseAsValue(aValue, aResult);
+      net::ParseAsValue(aValue, aResult);
       return true;
     }
 
@@ -419,79 +419,13 @@ void HTMLLinkElement::GetAs(nsAString& aResult) {
   GetEnumAttr(nsGkAtoms::as, "", aResult);
 }
 
-enum ASDestination : uint8_t {
-  DESTINATION_INVALID,
-  DESTINATION_AUDIO,
-  DESTINATION_DOCUMENT,
-  DESTINATION_EMBED,
-  DESTINATION_FONT,
-  DESTINATION_IMAGE,
-  DESTINATION_MANIFEST,
-  DESTINATION_OBJECT,
-  DESTINATION_REPORT,
-  DESTINATION_SCRIPT,
-  DESTINATION_SERVICEWORKER,
-  DESTINATION_SHAREDWORKER,
-  DESTINATION_STYLE,
-  DESTINATION_TRACK,
-  DESTINATION_VIDEO,
-  DESTINATION_WORKER,
-  DESTINATION_XSLT,
-  DESTINATION_FETCH
-};
-
-static const nsAttrValue::EnumTable kAsAttributeTable[] = {
-    {"", DESTINATION_INVALID},      {"audio", DESTINATION_AUDIO},
-    {"font", DESTINATION_FONT},     {"image", DESTINATION_IMAGE},
-    {"script", DESTINATION_SCRIPT}, {"style", DESTINATION_STYLE},
-    {"track", DESTINATION_TRACK},   {"video", DESTINATION_VIDEO},
-    {"fetch", DESTINATION_FETCH},   {nullptr, 0}};
-
-/* static */
-void HTMLLinkElement::ParseAsValue(const nsAString& aValue,
-                                   nsAttrValue& aResult) {
-  DebugOnly<bool> success =
-      aResult.ParseEnumValue(aValue, kAsAttributeTable, false,
-                             // default value is a empty string
-                             // if aValue is not a value we
-                             // understand
-                             &kAsAttributeTable[0]);
-  MOZ_ASSERT(success);
-}
-
-/* static */
-nsContentPolicyType HTMLLinkElement::AsValueToContentPolicy(
-    const nsAttrValue& aValue) {
-  switch (aValue.GetEnumValue()) {
-    case DESTINATION_INVALID:
-      return nsIContentPolicy::TYPE_INVALID;
-    case DESTINATION_AUDIO:
-      return nsIContentPolicy::TYPE_INTERNAL_AUDIO;
-    case DESTINATION_TRACK:
-      return nsIContentPolicy::TYPE_INTERNAL_TRACK;
-    case DESTINATION_VIDEO:
-      return nsIContentPolicy::TYPE_INTERNAL_VIDEO;
-    case DESTINATION_FONT:
-      return nsIContentPolicy::TYPE_FONT;
-    case DESTINATION_IMAGE:
-      return nsIContentPolicy::TYPE_IMAGE;
-    case DESTINATION_SCRIPT:
-      return nsIContentPolicy::TYPE_SCRIPT;
-    case DESTINATION_STYLE:
-      return nsIContentPolicy::TYPE_STYLESHEET;
-    case DESTINATION_FETCH:
-      return nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD;
-  }
-  return nsIContentPolicy::TYPE_INVALID;
-}
-
 void HTMLLinkElement::GetContentPolicyMimeTypeMedia(
     nsAttrValue& aAsAttr, nsContentPolicyType& aPolicyType, nsString& aMimeType,
     nsAString& aMedia) {
   nsAutoString as;
   GetAttr(kNameSpaceID_None, nsGkAtoms::as, as);
-  ParseAsValue(as, aAsAttr);
-  aPolicyType = AsValueToContentPolicy(aAsAttr);
+  net::ParseAsValue(as, aAsAttr);
+  aPolicyType = net::AsValueToContentPolicy(aAsAttr);
 
   nsAutoString type;
   GetAttr(kNameSpaceID_None, nsGkAtoms::type, type);
@@ -542,9 +476,9 @@ void HTMLLinkElement::
       GetContentPolicyMimeTypeMedia(asAttr, policyType, mimeType, media);
 
       if (policyType == nsIContentPolicy::TYPE_INVALID ||
-          !CheckPreloadAttrs(asAttr, mimeType, media, OwnerDoc())) {
+          !net::CheckPreloadAttrs(asAttr, mimeType, media, OwnerDoc())) {
         // Ignore preload with a wrong or empty as attribute.
-        WarnIgnoredPreload(*OwnerDoc(), *uri);
+        net::WarnIgnoredPreload(*OwnerDoc(), *uri);
         return;
       }
 
@@ -601,11 +535,11 @@ void HTMLLinkElement::UpdatePreload(nsAtom* aName, const nsAttrValue* aValue,
   GetContentPolicyMimeTypeMedia(asAttr, asPolicyType, mimeType, media);
 
   if (asPolicyType == nsIContentPolicy::TYPE_INVALID ||
-      !CheckPreloadAttrs(asAttr, mimeType, media, OwnerDoc())) {
+      !net::CheckPreloadAttrs(asAttr, mimeType, media, OwnerDoc())) {
     // Ignore preload with a wrong or empty as attribute, but be sure to cancel
     // the old one.
     CancelPrefetchOrPreload();
-    WarnIgnoredPreload(*OwnerDoc(), *uri);
+    net::WarnIgnoredPreload(*OwnerDoc(), *uri);
     return;
   }
 
@@ -623,8 +557,8 @@ void HTMLLinkElement::UpdatePreload(nsAtom* aName, const nsAttrValue* aValue,
 
   if (aName == nsGkAtoms::as) {
     if (aOldValue) {
-      oldPolicyType = AsValueToContentPolicy(*aOldValue);
-      if (!CheckPreloadAttrs(*aOldValue, mimeType, media, OwnerDoc())) {
+      oldPolicyType = net::AsValueToContentPolicy(*aOldValue);
+      if (!net::CheckPreloadAttrs(*aOldValue, mimeType, media, OwnerDoc())) {
         oldPolicyType = nsIContentPolicy::TYPE_INVALID;
       }
     } else {
@@ -638,7 +572,7 @@ void HTMLLinkElement::UpdatePreload(nsAtom* aName, const nsAttrValue* aValue,
     }
     nsAutoString oldMimeType;
     nsContentUtils::SplitMimeType(oldType, oldMimeType, notUsed);
-    if (CheckPreloadAttrs(asAttr, oldMimeType, media, OwnerDoc())) {
+    if (net::CheckPreloadAttrs(asAttr, oldMimeType, media, OwnerDoc())) {
       oldPolicyType = asPolicyType;
     } else {
       oldPolicyType = nsIContentPolicy::TYPE_INVALID;
@@ -649,7 +583,7 @@ void HTMLLinkElement::UpdatePreload(nsAtom* aName, const nsAttrValue* aValue,
     if (aOldValue) {
       aOldValue->ToString(oldMedia);
     }
-    if (CheckPreloadAttrs(asAttr, mimeType, oldMedia, OwnerDoc())) {
+    if (net::CheckPreloadAttrs(asAttr, mimeType, oldMedia, OwnerDoc())) {
       oldPolicyType = asPolicyType;
     } else {
       oldPolicyType = nsIContentPolicy::TYPE_INVALID;
@@ -695,95 +629,6 @@ void HTMLLinkElement::CancelPreload() {
   }
 }
 
-// We will use official mime-types from:
-// https://www.iana.org/assignments/media-types/media-types.xhtml#font
-// We do not support old deprecated mime-types for preload feature.
-// (We currectly do not support font/collection)
-static uint32_t StyleLinkElementFontMimeTypesNum = 5;
-static const char* StyleLinkElementFontMimeTypes[] = {
-    "font/otf", "font/sfnt", "font/ttf", "font/woff", "font/woff2"};
-
-bool IsFontMimeType(const nsAString& aType) {
-  if (aType.IsEmpty()) {
-    return true;
-  }
-  for (uint32_t i = 0; i < StyleLinkElementFontMimeTypesNum; i++) {
-    if (aType.EqualsASCII(StyleLinkElementFontMimeTypes[i])) {
-      return true;
-    }
-  }
-  return false;
-}
-
-bool HTMLLinkElement::CheckPreloadAttrs(const nsAttrValue& aAs,
-                                        const nsAString& aType,
-                                        const nsAString& aMedia,
-                                        Document* aDocument) {
-  nsContentPolicyType policyType = AsValueToContentPolicy(aAs);
-  if (policyType == nsIContentPolicy::TYPE_INVALID) {
-    return false;
-  }
-
-  // Check if media attribute is valid.
-  if (!aMedia.IsEmpty()) {
-    RefPtr<MediaList> mediaList =
-        MediaList::Create(NS_ConvertUTF16toUTF8(aMedia));
-    if (!mediaList->Matches(*aDocument)) {
-      return false;
-    }
-  }
-
-  if (aType.IsEmpty()) {
-    return true;
-  }
-
-  if (policyType == nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD) {
-    return true;
-  }
-
-  nsAutoString type(aType);
-  ToLowerCase(type);
-  if (policyType == nsIContentPolicy::TYPE_MEDIA) {
-    if (aAs.GetEnumValue() == DESTINATION_TRACK) {
-      return type.EqualsASCII("text/vtt");
-    }
-    Maybe<MediaContainerType> mimeType = MakeMediaContainerType(aType);
-    if (!mimeType) {
-      return false;
-    }
-    DecoderDoctorDiagnostics diagnostics;
-    CanPlayStatus status =
-        DecoderTraits::CanHandleContainerType(*mimeType, &diagnostics);
-    // Preload if this return CANPLAY_YES and CANPLAY_MAYBE.
-    return status != CANPLAY_NO;
-  }
-  if (policyType == nsIContentPolicy::TYPE_FONT) {
-    return IsFontMimeType(type);
-  }
-  if (policyType == nsIContentPolicy::TYPE_IMAGE) {
-    return imgLoader::SupportImageWithMimeType(
-        NS_ConvertUTF16toUTF8(type), AcceptedMimeTypes::IMAGES_AND_DOCUMENTS);
-  }
-  if (policyType == nsIContentPolicy::TYPE_SCRIPT) {
-    return nsContentUtils::IsJavascriptMIMEType(type);
-  }
-  if (policyType == nsIContentPolicy::TYPE_STYLESHEET) {
-    return type.EqualsASCII("text/css");
-  }
-  return false;
-}
-
-void HTMLLinkElement::WarnIgnoredPreload(const Document& aDoc, nsIURI& aURI) {
-  AutoTArray<nsString, 1> params;
-  {
-    nsCString uri = nsContentUtils::TruncatedURLForDisplay(&aURI);
-    AppendUTF8toUTF16(uri, *params.AppendElement());
-  }
-  nsContentUtils::ReportToConsole(nsIScriptError::warningFlag, "DOM"_ns, &aDoc,
-                                  nsContentUtils::eDOM_PROPERTIES,
-                                  "PreloadIgnoredInvalidAttr", params);
-}
-
 bool HTMLLinkElement::IsCSSMimeTypeAttributeForLinkElement(
     const Element& aSelf) {
   // Processing the type attribute per
diff --git a/dom/html/HTMLLinkElement.h b/dom/html/HTMLLinkElement.h
index 2d1c00353287..64edde509cdf 100644
--- a/dom/html/HTMLLinkElement.h
+++ b/dom/html/HTMLLinkElement.h
@@ -115,9 +115,6 @@ class HTMLLinkElement final : public nsGenericHTMLElement,
     SetAttr(nsGkAtoms::as, aAs, aRv);
   }
 
-  static void ParseAsValue(const nsAString& aValue, nsAttrValue& aResult);
-  static nsContentPolicyType AsValueToContentPolicy(const nsAttrValue& aValue);
-
   nsDOMTokenList* Sizes() {
     if (!mSizes) {
       mSizes = new nsDOMTokenList(this, nsGkAtoms::sizes);
@@ -176,10 +173,6 @@ class HTMLLinkElement final : public nsGenericHTMLElement,
     nsGenericHTMLElement::NodeInfoChanged(aOldDoc);
   }
 
-  static bool CheckPreloadAttrs(const nsAttrValue& aAs, const nsAString& aType,
-                                const nsAString& aMedia, Document* aDocument);
-  static void WarnIgnoredPreload(const Document&, nsIURI&);
-
  protected:
   virtual ~HTMLLinkElement();
 
diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index 9d53ee5c9540..61cb735069d2 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -5,6 +5,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 // HttpLog.h should generally be included first
+#include "DecoderDoctorDiagnostics.h"
 #include "HttpLog.h"
 
 #include "nsNetUtil.h"
@@ -105,6 +106,10 @@
 #include "nsParserConstants.h"
 #include "nsCRT.h"
 #include "nsServiceManagerUtils.h"
+#include "mozilla/dom/MediaList.h"
+#include "MediaContainerType.h"
+#include "DecoderTraits.h"
+#include "imgLoader.h"
 
 #if defined(MOZ_THUNDERBIRD) || defined(MOZ_SUITE)
 #  include "nsNewMailnewsURI.h"
@@ -3662,6 +3667,135 @@ nsTArray<LinkHeader> ParseLinkHeader(const nsAString& aLinkData) {
   return linkHeaders;
 }
 
+// We will use official mime-types from:
+// https://www.iana.org/assignments/media-types/media-types.xhtml#font
+// We do not support old deprecated mime-types for preload feature.
+// (We currectly do not support font/collection)
+static uint32_t StyleLinkElementFontMimeTypesNum = 5;
+static const char* StyleLinkElementFontMimeTypes[] = {
+    "font/otf", "font/sfnt", "font/ttf", "font/woff", "font/woff2"};
+
+bool IsFontMimeType(const nsAString& aType) {
+  if (aType.IsEmpty()) {
+    return true;
+  }
+  for (uint32_t i = 0; i < StyleLinkElementFontMimeTypesNum; i++) {
+    if (aType.EqualsASCII(StyleLinkElementFontMimeTypes[i])) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static const nsAttrValue::EnumTable kAsAttributeTable[] = {
+    {"", DESTINATION_INVALID},      {"audio", DESTINATION_AUDIO},
+    {"font", DESTINATION_FONT},     {"image", DESTINATION_IMAGE},
+    {"script", DESTINATION_SCRIPT}, {"style", DESTINATION_STYLE},
+    {"track", DESTINATION_TRACK},   {"video", DESTINATION_VIDEO},
+    {"fetch", DESTINATION_FETCH},   {nullptr, 0}};
+
+void ParseAsValue(const nsAString& aValue, nsAttrValue& aResult) {
+  DebugOnly<bool> success =
+      aResult.ParseEnumValue(aValue, kAsAttributeTable, false,
+                             // default value is a empty string
+                             // if aValue is not a value we
+                             // understand
+                             &kAsAttributeTable[0]);
+  MOZ_ASSERT(success);
+}
+
+nsContentPolicyType AsValueToContentPolicy(const nsAttrValue& aValue) {
+  switch (aValue.GetEnumValue()) {
+    case DESTINATION_INVALID:
+      return nsIContentPolicy::TYPE_INVALID;
+    case DESTINATION_AUDIO:
+      return nsIContentPolicy::TYPE_INTERNAL_AUDIO;
+    case DESTINATION_TRACK:
+      return nsIContentPolicy::TYPE_INTERNAL_TRACK;
+    case DESTINATION_VIDEO:
+      return nsIContentPolicy::TYPE_INTERNAL_VIDEO;
+    case DESTINATION_FONT:
+      return nsIContentPolicy::TYPE_FONT;
+    case DESTINATION_IMAGE:
+      return nsIContentPolicy::TYPE_IMAGE;
+    case DESTINATION_SCRIPT:
+      return nsIContentPolicy::TYPE_SCRIPT;
+    case DESTINATION_STYLE:
+      return nsIContentPolicy::TYPE_STYLESHEET;
+    case DESTINATION_FETCH:
+      return nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD;
+  }
+  return nsIContentPolicy::TYPE_INVALID;
+}
+
+bool CheckPreloadAttrs(const nsAttrValue& aAs, const nsAString& aType,
+                       const nsAString& aMedia,
+                       mozilla::dom::Document* aDocument) {
+  nsContentPolicyType policyType = AsValueToContentPolicy(aAs);
+  if (policyType == nsIContentPolicy::TYPE_INVALID) {
+    return false;
+  }
+
+  // Check if media attribute is valid.
+  if (!aMedia.IsEmpty()) {
+    RefPtr<mozilla::dom::MediaList> mediaList =
+        mozilla::dom::MediaList::Create(NS_ConvertUTF16toUTF8(aMedia));
+    if (!mediaList->Matches(*aDocument)) {
+      return false;
+    }
+  }
+
+  if (aType.IsEmpty()) {
+    return true;
+  }
+
+  if (policyType == nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD) {
+    return true;
+  }
+
+  nsAutoString type(aType);
+  ToLowerCase(type);
+  if (policyType == nsIContentPolicy::TYPE_MEDIA) {
+    if (aAs.GetEnumValue() == DESTINATION_TRACK) {
+      return type.EqualsASCII("text/vtt");
+    }
+    Maybe<MediaContainerType> mimeType = MakeMediaContainerType(aType);
+    if (!mimeType) {
+      return false;
+    }
+    DecoderDoctorDiagnostics diagnostics;
+    CanPlayStatus status =
+        DecoderTraits::CanHandleContainerType(*mimeType, &diagnostics);
+    // Preload if this return CANPLAY_YES and CANPLAY_MAYBE.
+    return status != CANPLAY_NO;
+  }
+  if (policyType == nsIContentPolicy::TYPE_FONT) {
+    return IsFontMimeType(type);
+  }
+  if (policyType == nsIContentPolicy::TYPE_IMAGE) {
+    return imgLoader::SupportImageWithMimeType(
+        NS_ConvertUTF16toUTF8(type), AcceptedMimeTypes::IMAGES_AND_DOCUMENTS);
+  }
+  if (policyType == nsIContentPolicy::TYPE_SCRIPT) {
+    return nsContentUtils::IsJavascriptMIMEType(type);
+  }
+  if (policyType == nsIContentPolicy::TYPE_STYLESHEET) {
+    return type.EqualsASCII("text/css");
+  }
+  return false;
+}
+
+void WarnIgnoredPreload(const mozilla::dom::Document& aDoc, nsIURI& aURI) {
+  AutoTArray<nsString, 1> params;
+  {
+    nsCString uri = nsContentUtils::TruncatedURLForDisplay(&aURI);
+    AppendUTF8toUTF16(uri, *params.AppendElement());
+  }
+  nsContentUtils::ReportToConsole(nsIScriptError::warningFlag, "DOM"_ns, &aDoc,
+                                  nsContentUtils::eDOM_PROPERTIES,
+                                  "PreloadIgnoredInvalidAttr", params);
+}
+
 }  // namespace net
 }  // namespace mozilla
 
diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
index 7d62296b9bc3..b17ac5780a49 100644
--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -10,6 +10,7 @@
 #include <functional>
 #include "mozilla/Maybe.h"
 #include "mozilla/ResultExtensions.h"
+#include "nsAttrValue.h"
 #include "nsCOMPtr.h"
 #include "nsIInterfaceRequestor.h"
 #include "nsIInterfaceRequestorUtils.h"
@@ -1016,6 +1017,34 @@ struct LinkHeader {
 
 nsTArray<LinkHeader> ParseLinkHeader(const nsAString& aLinkData);
 
+enum ASDestination : uint8_t {
+  DESTINATION_INVALID,
+  DESTINATION_AUDIO,
+  DESTINATION_DOCUMENT,
+  DESTINATION_EMBED,
+  DESTINATION_FONT,
+  DESTINATION_IMAGE,
+  DESTINATION_MANIFEST,
+  DESTINATION_OBJECT,
+  DESTINATION_REPORT,
+  DESTINATION_SCRIPT,
+  DESTINATION_SERVICEWORKER,
+  DESTINATION_SHAREDWORKER,
+  DESTINATION_STYLE,
+  DESTINATION_TRACK,
+  DESTINATION_VIDEO,
+  DESTINATION_WORKER,
+  DESTINATION_XSLT,
+  DESTINATION_FETCH
+};
+
+void ParseAsValue(const nsAString& aValue, nsAttrValue& aResult);
+nsContentPolicyType AsValueToContentPolicy(const nsAttrValue& aValue);
+
+bool CheckPreloadAttrs(const nsAttrValue& aAs, const nsAString& aType,
+                       const nsAString& aMedia,
+                       mozilla::dom::Document* aDocument);
+void WarnIgnoredPreload(const mozilla::dom::Document&, nsIURI&);
 }  // namespace net
 }  // namespace mozilla