Bug 1708422: part 10) Factor `ShouldSpellCheckRange` out. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D114104

extensions/spellcheck/src/mozInlineSpellChecker.cpp

@@ -1296,6 +1296,8 @@ class MOZ_STACK_CLASS mozInlineSpellChecker::SpellCheckerTimeSlice {
   void CheckWordsAndAddRangesForMisspellings(
       const nsTArray<nsString>& aWords, nsTArray<NodeOffsetRange>&& aRanges);
 
+  bool ShouldSpellCheckRange(const nsRange& aRange) const;
+
   mozInlineSpellChecker& mInlineSpellChecker;
   mozInlineSpellWordUtil& mWordUtil;
   mozilla::dom::Selection& mSpellCheckSelection;
@@ -1303,6 +1305,17 @@ class MOZ_STACK_CLASS mozInlineSpellChecker::SpellCheckerTimeSlice {
   bool& mDoneChecking;
 };
 
+bool mozInlineSpellChecker::SpellCheckerTimeSlice::ShouldSpellCheckRange(
+    const nsRange& aRange) const {
+  nsINode* beginNode = aRange.GetStartContainer();
+  nsINode* endNode = aRange.GetEndContainer();
+
+  const nsINode* rootNode = mWordUtil.GetRootNode();
+  return beginNode->IsInComposedDoc() && endNode->IsInComposedDoc() &&
+         beginNode->IsShadowIncludingInclusiveDescendantOf(rootNode) &&
+         endNode->IsShadowIncludingInclusiveDescendantOf(rootNode);
+}
+
 // mozInlineSpellChecker::SpellCheckerTimeSlice::Execute
 //
 //    This function checks words intersecting the given range, excluding those
@@ -1372,12 +1385,7 @@ nsresult mozInlineSpellChecker::SpellCheckerTimeSlice::Execute() {
     nsINode* endNode = mStatus->mRange->GetEndContainer();
     int32_t endOffset = mStatus->mRange->EndOffset();
 
-    // Now check that we're still looking at a range that's under
-    // aWordUtil.GetRootNode()
-    const nsINode* rootNode = mWordUtil.GetRootNode();
-    if (!beginNode->IsInComposedDoc() || !endNode->IsInComposedDoc() ||
-        !beginNode->IsShadowIncludingInclusiveDescendantOf(rootNode) ||
-        !endNode->IsShadowIncludingInclusiveDescendantOf(rootNode)) {
+    if (!ShouldSpellCheckRange(*mStatus->mRange)) {
       // Just bail out and don't try to spell-check this
       return NS_OK;
     }