Bug 1628043 - Have GetFrameForPoint and GetFramesForArea take a const nsIFrame*. r=tnikkel

This allows us to have a single const_cast inside GetFramesForArea, and
avoid several callers of these functions (which, as of bug 1556556,
get a const nsIFrame* from RelativeTo inputs) having to const_cast.

Differential Revision: https://phabricator.services.mozilla.com/D70068

--HG--
extra : moz-landing-system : lando

layout/base/nsLayoutUtils.cpp

@@ -3141,7 +3141,8 @@ struct AutoNestedPaintCount {
 #endif
 
 nsIFrame* nsLayoutUtils::GetFrameForPoint(
-    nsIFrame* aFrame, nsPoint aPt, EnumSet<FrameForPointOption> aOptions) {
+    const nsIFrame* aFrame, nsPoint aPt,
+    EnumSet<FrameForPointOption> aOptions) {
   AUTO_PROFILER_LABEL("nsLayoutUtils::GetFrameForPoint", LAYOUT);
 
   nsresult rv;
@@ -3152,11 +3153,13 @@ nsIFrame* nsLayoutUtils::GetFrameForPoint(
 }
 
 nsresult nsLayoutUtils::GetFramesForArea(
-    nsIFrame* aFrame, const nsRect& aRect, nsTArray<nsIFrame*>& aOutFrames,
-    EnumSet<FrameForPointOption> aOptions) {
+    const nsIFrame* aFrame, const nsRect& aRect,
+    nsTArray<nsIFrame*>& aOutFrames, EnumSet<FrameForPointOption> aOptions) {
   AUTO_PROFILER_LABEL("nsLayoutUtils::GetFramesForArea", LAYOUT);
 
-  nsDisplayListBuilder builder(aFrame, nsDisplayListBuilderMode::EventDelivery,
+  nsIFrame* frame = const_cast<nsIFrame*>(aFrame);
+
+  nsDisplayListBuilder builder(frame, nsDisplayListBuilderMode::EventDelivery,
                                false);
   builder.BeginFrame();
   nsDisplayList list;
@@ -3177,13 +3180,13 @@ nsresult nsLayoutUtils::GetFramesForArea(
   builder.SetHitTestIsForVisibility(
       aOptions.contains(FrameForPointOption::OnlyVisible));
 
-  builder.EnterPresShell(aFrame);
+  builder.EnterPresShell(frame);
 
   builder.SetVisibleRect(aRect);
   builder.SetDirtyRect(aRect);
 
-  aFrame->BuildDisplayListForStackingContext(&builder, &list);
-  builder.LeavePresShell(aFrame, nullptr);
+  frame->BuildDisplayListForStackingContext(&builder, &list);
+  builder.LeavePresShell(frame, nullptr);
 
 #ifdef MOZ_DUMP_PAINTING
   if (gDumpEventList) {

layout/base/nsLayoutUtils.h

@@ -881,7 +881,7 @@ class nsLayoutUtils {
    * @param aPt the point, relative to the frame origin
    * @param aFlags some combination of FrameForPointOption.
    */
-  static nsIFrame* GetFrameForPoint(nsIFrame* aFrame, nsPoint aPt,
+  static nsIFrame* GetFrameForPoint(const nsIFrame* aFrame, nsPoint aPt,
                                     mozilla::EnumSet<FrameForPointOption> = {});
 
   /**
@@ -892,7 +892,7 @@ class nsLayoutUtils {
    * @param aOutFrames an array to add all the frames found
    * @param aFlags some combination of FrameForPointOption.
    */
-  static nsresult GetFramesForArea(nsIFrame* aFrame, const nsRect& aRect,
+  static nsresult GetFramesForArea(const nsIFrame* aFrame, const nsRect& aRect,
                                    nsTArray<nsIFrame*>& aOutFrames,
                                    mozilla::EnumSet<FrameForPointOption> = {});