Bug 1675614 - Process spellcheck in chunks in the parent process, since it's also async. r=m_kato

Differential Revision: https://phabricator.services.mozilla.com/D109692

extensions/spellcheck/src/mozInlineSpellChecker.cpp

@@ -1315,9 +1315,8 @@ nsresult mozInlineSpellChecker::DoSpellCheck(
   nsAutoString wordText;
   NodeOffsetRange wordNodeOffsetRange;
   bool dontCheckWord;
-  // XXX Spellchecker API isn't async on chrome process.
   static const size_t requestChunkSize =
-      XRE_IsContentProcess() ? INLINESPELL_MAXIMUM_CHUNKED_WORDS_PER_TASK : 1;
+      INLINESPELL_MAXIMUM_CHUNKED_WORDS_PER_TASK;
   while (
       aWordUtil.GetNextWord(wordText, &wordNodeOffsetRange, &dontCheckWord)) {
     // get the range for the current word.