Bug 1633448: part 7) Add `StyledRanges::UnregisterSelection`. r=hsivonen

One step closer towards privatizing `StyledRanges::mRanges`.

Depends on D73234

Differential Revision: https://phabricator.services.mozilla.com/D73430

dom/base/Selection.cpp

@@ -541,10 +541,7 @@ Selection::~Selection() { Disconnect(); }
 void Selection::Disconnect() {
   SetAnchorFocusRange(-1);
 
-  uint32_t count = mStyledRanges.mRanges.Length();
+  mStyledRanges.UnregisterSelection();
-  for (uint32_t i = 0; i < count; ++i) {
-    mStyledRanges.mRanges[i].mRange->UnregisterSelection();
-  }
 
   if (mAutoScrollTimer) {
     mAutoScrollTimer->Stop();
@@ -1109,8 +1106,8 @@ nsresult Selection::RemoveCollapsedRanges() {
 nsresult Selection::Clear(nsPresContext* aPresContext) {
   SetAnchorFocusRange(-1);
 
+  mStyledRanges.UnregisterSelection();
   for (uint32_t i = 0; i < mStyledRanges.mRanges.Length(); ++i) {
-    mStyledRanges.mRanges[i].mRange->UnregisterSelection();
     SelectFrames(aPresContext, mStyledRanges.mRanges[i].mRange, false);
   }
   mStyledRanges.mRanges.Clear();
@@ -1749,6 +1746,13 @@ void Selection::SetAncestorLimiter(nsIContent* aLimiter) {
   }
 }
 
+void Selection::StyledRanges::UnregisterSelection() {
+  uint32_t count = mRanges.Length();
+  for (uint32_t i = 0; i < count; ++i) {
+    mRanges[i].mRange->UnregisterSelection();
+  }
+}
+
 StyledRange* Selection::StyledRanges::FindRangeData(nsRange* aRange) {
   NS_ENSURE_TRUE(aRange, nullptr);
   for (uint32_t i = 0; i < mRanges.Length(); i++) {

dom/base/Selection.h

@@ -841,6 +841,8 @@ class Selection final : public nsSupportsWeakReference,
     static nsresult SubtractRange(StyledRange& aRange, nsRange& aSubtract,
                                   nsTArray<StyledRange>* aOutput);
 
+    void UnregisterSelection();
+
     // These are the ranges inside this selection. They are kept sorted in order
     // of DOM start position.
     //