From b1029e4f2815385c5a0c3522e9af063cd49f1d92 Mon Sep 17 00:00:00 2001
From: Agi Sferro <agi@sferro.dev>
Date: Fri, 9 Oct 2020 17:31:52 +0000
Subject: [PATCH] Bug 1648157 - Add parameter to not iterate subdocs on media
 change. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D92807
---
 layout/base/nsPresContext.cpp | 22 +++++++++++++---------
 layout/base/nsPresContext.h   |  5 ++++-
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index 2ffe68754986..f41799a5cea2 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -1542,7 +1542,8 @@ void nsPresContext::PostRebuildAllStyleDataEvent(
 }
 
 void nsPresContext::MediaFeatureValuesChangedAllDocuments(
-    const MediaFeatureChange& aChange) {
+    const MediaFeatureChange& aChange,
+    RecurseIntoInProcessSubDocuments aRecurseSubDocuments) {
   // Handle the media feature value change in this document.
   MediaFeatureValuesChanged(aChange);
 
@@ -1550,14 +1551,17 @@ void nsPresContext::MediaFeatureValuesChangedAllDocuments(
   // document is using.
   mDocument->ImageTracker()->MediaFeatureValuesChangedAllDocuments(aChange);
 
-  // And then into any subdocuments.
-  auto recurse = [&aChange](dom::Document& aSubDoc) {
-    if (nsPresContext* pc = aSubDoc.GetPresContext()) {
-      pc->MediaFeatureValuesChangedAllDocuments(aChange);
-    }
-    return CallState::Continue;
-  };
-  mDocument->EnumerateSubDocuments(recurse);
+  if (aRecurseSubDocuments == RecurseIntoInProcessSubDocuments::Yes) {
+    // And then into any subdocuments.
+    auto recurse = [&aChange, aRecurseSubDocuments](dom::Document& aSubDoc) {
+      if (nsPresContext* pc = aSubDoc.GetPresContext()) {
+        pc->MediaFeatureValuesChangedAllDocuments(aChange,
+                                                  aRecurseSubDocuments);
+      }
+      return CallState::Continue;
+    };
+    mDocument->EnumerateSubDocuments(recurse);
+  }
 }
 
 void nsPresContext::FlushPendingMediaFeatureValuesChanged() {
diff --git a/layout/base/nsPresContext.h b/layout/base/nsPresContext.h
index 79c1583892a0..967dbdbea35b 100644
--- a/layout/base/nsPresContext.h
+++ b/layout/base/nsPresContext.h
@@ -283,6 +283,8 @@ class nsPresContext : public nsISupports, public mozilla::SupportsWeakPtr {
 
   void ContentLanguageChanged();
 
+  enum class RecurseIntoInProcessSubDocuments : bool { No, Yes };
+
   /**
    * Handle changes in the values of media features (used in media queries).
    */
@@ -296,7 +298,8 @@ class nsPresContext : public nsISupports, public mozilla::SupportsWeakPtr {
    * features that must be updated in all subdocuments e.g. display-mode.
    */
   void MediaFeatureValuesChangedAllDocuments(
-      const mozilla::MediaFeatureChange&);
+      const mozilla::MediaFeatureChange&,
+      RecurseIntoInProcessSubDocuments = RecurseIntoInProcessSubDocuments::Yes);
 
   /**
    * Updates the size mode on all remote children and recursively notifies this