tor-browser

commit 8614bf2a9ac69a52f070a91e747ecaf6710c60c4
parent a462b9fb10c3e1e3ffbe71b18fd361c6c73bfba2
Author: Emilio Cobos Álvarez <emilio@crisal.io>
Date:   Fri,  3 Oct 2025 11:33:41 +0000

Bug 1986711 - Closed menupopups shouldn't have an intrinsic size. r=layout-reviewers,dshin

We already avoid most of the reflow work during Reflow(), but this
code-path can still be expensive. We get it to try to compute the
hypothetical position of a popup, which arguably we should never need to
begin with, but this seems trivial to do here.

Differential Revision: https://phabricator.services.mozilla.com/D267288

Diffstat:
M
layout/xul/nsMenuPopupFrame.cpp
 | 
33
++++++++++++++++++---------------
M
layout/xul/nsMenuPopupFrame.h
 | 
5
+++--

2 files changed, 21 insertions(+), 17 deletions(-)
diff --git a/layout/xul/nsMenuPopupFrame.cpp b/layout/xul/nsMenuPopupFrame.cpp
@@ -500,6 +500,9 @@ void nsMenuPopupFrame::DidSetComputedStyle(ComputedStyle* aOldStyle) {
 
 nscoord nsMenuPopupFrame::IntrinsicISize(const IntrinsicSizeInput& aInput,
                                          IntrinsicISizeType aType) {
+  if (CanSkipLayout()) {
+    return 0;
+  }
   nscoord iSize = nsBlockFrame::IntrinsicISize(aInput, aType);
   if (!ShouldExpandToInflowParentOrAnchor()) {
     return iSize;
@@ -566,6 +569,18 @@ void nsMenuPopupFrame::EnsureActiveMenuListItemIsVisible() {
       ScrollFlags::ScrollOverflowHidden | ScrollFlags::ScrollFirstAncestorOnly);
 }
 
+bool nsMenuPopupFrame::CanSkipLayout() const {
+  // If the popup is not open, only do layout while showing or if we're a
+  // menulist.
+  //
+  // The later is needed because the SelectParent code wants to limit the height
+  // of the popup before opening it.
+  //
+  // TODO(emilio): We should consider adding a way to do that more reliably
+  // instead, but this preserves existing behavior.
+  return !IsVisibleOrShowing() && !IsMenuList();
+}
+
 void nsMenuPopupFrame::LayoutPopup(nsPresContext* aPresContext,
                                    ReflowOutput& aDesiredSize,
                                    const ReflowInput& aReflowInput,
@@ -577,21 +592,9 @@ void nsMenuPopupFrame::LayoutPopup(nsPresContext* aPresContext,
   SchedulePaint();
 
   const bool isOpen = IsOpen();
-  if (!isOpen) {
-    // If the popup is not open, only do layout while showing or if we're a
-    // menulist.
-    //
-    // This is needed because the SelectParent code wants to limit the height of
-    // the popup before opening it.
-    //
-    // TODO(emilio): We should consider adding a way to do that more reliably
-    // instead, but this preserves existing behavior.
-    const bool needsLayout = mPopupState == ePopupShowing ||
-                             mPopupState == ePopupPositioning || IsMenuList();
-    if (!needsLayout) {
-      RemoveStateBits(NS_FRAME_FIRST_REFLOW);
-      return;
-    }
+  if (CanSkipLayout()) {
+    RemoveStateBits(NS_FRAME_FIRST_REFLOW);
+    return;
   }
 
   // Do a first reflow, with all our content, in order to find our preferred
diff --git a/layout/xul/nsMenuPopupFrame.h b/layout/xul/nsMenuPopupFrame.h
@@ -266,14 +266,15 @@ class nsMenuPopupFrame final : public nsBlockFrame {
     return mPopupState == ePopupOpening || mPopupState == ePopupVisible ||
            mPopupState == ePopupShown;
   }
-  bool IsVisible() {
+  bool IsVisible() const {
     return mPopupState == ePopupVisible || mPopupState == ePopupShown;
   }
-  bool IsVisibleOrShowing() {
+  bool IsVisibleOrShowing() const {
     return IsOpen() || mPopupState == ePopupPositioning ||
            mPopupState == ePopupShowing;
   }
   bool IsNativeMenu() const { return mIsNativeMenu; }
+  bool CanSkipLayout() const;
   bool IsMouseTransparent() const;
 
   // Return true if the popup is for a menulist.