Bug 1909142 part 1: Add Selection and nsFrameSelection getters to enable the accessibility engine to query custom highlight information. r=jjaschke

Differential Revision: https://phabricator.services.mozilla.com/D233805

dom/base/Selection.cpp

@@ -4445,7 +4445,7 @@ void Selection::SetColors(const nsAString& aForegroundColor,
 void Selection::ResetColors() { mCustomColors = nullptr; }
 
 void Selection::SetHighlightSelectionData(
-    HighlightSelectionData aHighlightSelectionData) {
+    struct HighlightSelectionData aHighlightSelectionData) {
   MOZ_ASSERT(mSelectionType == SelectionType::eHighlight);
   mHighlightData = std::move(aHighlightSelectionData);
 }

dom/base/Selection.h

@@ -604,6 +604,10 @@ class Selection final : public nsSupportsWeakReference,
   void SetHighlightSelectionData(
       HighlightSelectionData aHighlightSelectionData);
 
+  const HighlightSelectionData& HighlightSelectionData() const {
+    return mHighlightData;
+  }
+
   /**
    * See documentation of `GetRangesForInterval` in Selection.webidl.
    *
@@ -1123,7 +1127,7 @@ class Selection final : public nsSupportsWeakReference,
   CachedOffsetForFrame* mCachedOffsetForFrame;
   nsDirection mDirection;
   const SelectionType mSelectionType;
-  HighlightSelectionData mHighlightData;
+  struct HighlightSelectionData mHighlightData;
   UniquePtr<SelectionCustomColors> mCustomColors;
 
   // Non-zero if we don't want any changes we make to the selection to be

layout/generic/nsFrameSelection.h

@@ -466,6 +466,20 @@ class nsFrameSelection final {
     return *GetSelection(mozilla::SelectionType::eNormal);
   }
 
+  /**
+   * Returns the number of highlight selections.
+   */
+  size_t HighlightSelectionCount() const {
+    return mHighlightSelections.Length();
+  }
+
+  /**
+   * Get a highlight selection by index. The index must be valid.
+   */
+  RefPtr<mozilla::dom::Selection> HighlightSelection(size_t aIndex) const {
+    return mHighlightSelections[aIndex].second();
+  }
+
   /**
    * @brief Adds a highlight selection for `aHighlight`.
    */