--- a/editor/composer/nsEditorSpellCheck.cpp
+++ b/editor/composer/nsEditorSpellCheck.cpp
@@ -6,16 +6,17 @@
 
 #include <stdlib.h>                     // for getenv
 
 #include "mozilla/Attributes.h"         // for final
 #include "mozilla/dom/Element.h"        // for Element
 #include "mozilla/dom/Selection.h"
 #include "mozilla/intl/LocaleService.h" // for retrieving app locale
 #include "mozilla/mozalloc.h"           // for operator delete, etc
+#include "mozilla/mozSpellChecker.h"    // for mozSpellChecker
 #include "mozilla/Preferences.h"        // for Preferences
 #include "mozilla/TextServicesDocument.h" // for TextServicesDocument
 #include "nsAString.h"                  // for nsAString::IsEmpty, etc
 #include "nsComponentManagerUtils.h"    // for do_CreateInstance
 #include "nsDebug.h"                    // for NS_ENSURE_TRUE, etc
 #include "nsDependentSubstring.h"       // for Substring
 #include "nsEditorSpellCheck.h"
 #include "nsError.h"                    // for NS_ERROR_NOT_INITIALIZED, etc
@@ -23,17 +24,16 @@
 #include "nsIContentPrefService2.h"     // for nsIContentPrefService2, etc
 #include "nsIDOMDocument.h"             // for nsIDOMDocument
 #include "nsIDOMElement.h"              // for nsIDOMElement
 #include "nsIDocument.h"                // for nsIDocument
 #include "nsIEditor.h"                  // for nsIEditor
 #include "nsIHTMLEditor.h"              // for nsIHTMLEditor
 #include "nsILoadContext.h"
 #include "nsISelection.h"               // for nsISelection
-#include "nsISpellChecker.h"            // for nsISpellChecker, etc
 #include "nsISupportsBase.h"            // for nsISupports
 #include "nsISupportsUtils.h"           // for NS_ADDREF
 #include "nsITextServicesFilter.h"      // for nsITextServicesFilter
 #include "nsIURI.h"                     // for nsIURI
 #include "nsThreadUtils.h"              // for GetMainThreadSerialEventTarget
 #include "nsVariant.h"                  // for nsIWritableVariant, etc
 #include "nsLiteralString.h"            // for NS_LITERAL_STRING, etc
 #include "nsMemory.h"                   // for nsMemory
@@ -314,27 +314,27 @@ nsEditorSpellCheck::~nsEditorSpellCheck(
 // The problem is that if the spell checker does not exist, we can not tell
 // which dictionaries are installed. This function works around the problem,
 // allowing callers to ask if we can spell check without actually doing so (and
 // enabling or disabling UI as necessary). This just creates a spellcheck
 // object if needed and asks it for the dictionary list.
 NS_IMETHODIMP
 nsEditorSpellCheck::CanSpellCheck(bool* _retval)
 {
-  nsresult rv;
-  nsCOMPtr<nsISpellChecker> spellChecker;
-  if (! mSpellChecker) {
-    spellChecker = do_CreateInstance(NS_SPELLCHECKER_CONTRACTID, &rv);
-    NS_ENSURE_SUCCESS(rv, rv);
-  } else {
-    spellChecker = mSpellChecker;
+  RefPtr<mozSpellChecker> spellChecker = mSpellChecker;
+  if (!spellChecker) {
+    spellChecker = new mozSpellChecker();
+    DebugOnly<nsresult> rv = spellChecker->Init();
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
   }
   nsTArray<nsString> dictList;
-  rv = spellChecker->GetDictionaryList(&dictList);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsresult rv = spellChecker->GetDictionaryList(&dictList);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
 
   *_retval = (dictList.Length() > 0);
   return NS_OK;
 }
 
 // Instances of this class can be used as either runnables or RAII helpers.
 class CallbackCaller final : public Runnable
 {
@@ -415,21 +415,19 @@ nsEditorSpellCheck::InitSpellChecker(nsI
         // to iterate over the text in this range.
 
         rv = textServicesDocument->SetExtent(rangeBounds);
         NS_ENSURE_SUCCESS(rv, rv);
       }
     }
   }
 
-  mSpellChecker = do_CreateInstance(NS_SPELLCHECKER_CONTRACTID, &rv);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  NS_ENSURE_TRUE(mSpellChecker, NS_ERROR_NULL_POINTER);
-
+  mSpellChecker = new mozSpellChecker();
+  rv = mSpellChecker->Init();
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
   rv = mSpellChecker->SetDocument(textServicesDocument, true);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // do not fail if UpdateCurrentDictionary fails because this method may
   // succeed later.
   rv = UpdateCurrentDictionary(aCallback);
   if (NS_FAILED(rv) && aCallback) {
     // However, if it does fail, we still need to call the callback since we

--- a/editor/composer/nsEditorSpellCheck.h
+++ b/editor/composer/nsEditorSpellCheck.h
@@ -10,16 +10,17 @@
 #include "nsCOMPtr.h"                   // for nsCOMPtr
 #include "nsCycleCollectionParticipant.h"
 #include "nsIEditorSpellCheck.h"        // for NS_DECL_NSIEDITORSPELLCHECK, etc
 #include "nsISupportsImpl.h"
 #include "nsString.h"                   // for nsString
 #include "nsTArray.h"                   // for nsTArray
 #include "nscore.h"                     // for nsresult
 
+class mozSpellChecker;
 class nsIEditor;
 class nsISpellChecker;
 class nsITextServicesFilter;
 
 #define NS_EDITORSPELLCHECK_CID                     \
 { /* {75656ad9-bd13-4c5d-939a-ec6351eea0cc} */        \
     0x75656ad9, 0xbd13, 0x4c5d,                       \
     { 0x93, 0x9a, 0xec, 0x63, 0x51, 0xee, 0xa0, 0xcc }\
@@ -44,17 +45,17 @@ public:
   NS_DECL_CYCLE_COLLECTION_CLASS(nsEditorSpellCheck)
 
   /* Declare all methods in the nsIEditorSpellCheck interface */
   NS_DECL_NSIEDITORSPELLCHECK
 
 protected:
   virtual ~nsEditorSpellCheck();
 
-  nsCOMPtr<nsISpellChecker> mSpellChecker;
+  RefPtr<mozSpellChecker> mSpellChecker;
 
   nsTArray<nsString>  mSuggestedWordList;
   int32_t        mSuggestedWordIndex;
 
   // these are the words in the current personal dictionary,
   // GetPersonalDictionary must be called to load them.
   nsTArray<nsString>  mDictionaryList;
   int32_t        mDictionaryIndex;

--- a/extensions/spellcheck/src/mozSpellChecker.cpp
+++ b/extensions/spellcheck/src/mozSpellChecker.cpp
@@ -9,16 +9,17 @@
 #include "nsIStringEnumerator.h"
 #include "nsICategoryManager.h"
 #include "nsISupportsPrimitives.h"
 #include "nsISimpleEnumerator.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/PRemoteSpellcheckEngineChild.h"
 #include "mozilla/TextServicesDocument.h"
 #include "nsXULAppAPI.h"
+#include "RemoteSpellCheckEngineChild.h"
 
 using mozilla::dom::ContentChild;
 using mozilla::GenericPromise;
 using mozilla::PRemoteSpellcheckEngineChild;
 using mozilla::RemoteSpellcheckEngineChild;
 using mozilla::TextServicesDocument;
 
 #define DEFAULT_SPELL_CHECKER "@mozilla.org/spellchecker/engine;1"

--- a/extensions/spellcheck/src/mozSpellChecker.h
+++ b/extensions/spellcheck/src/mozSpellChecker.h
@@ -11,17 +11,16 @@
 #include "nsISpellChecker.h"
 #include "nsString.h"
 #include "mozIPersonalDictionary.h"
 #include "mozISpellCheckingEngine.h"
 #include "nsClassHashtable.h"
 #include "nsTArray.h"
 #include "mozISpellI18NUtil.h"
 #include "nsCycleCollectionParticipant.h"
-#include "RemoteSpellCheckEngineChild.h"
 
 namespace mozilla {
 class RemoteSpellcheckEngineChild;
 } // namespace mozilla
 
 class mozSpellChecker : public nsISpellChecker
 {
 public: