From 0f001155aa004f1a6679f386d49f64306fb54ab1 Mon Sep 17 00:00:00 2001
From: wolfbeast <mcwerewolf@wolfbeast.com>
Date: Sun, 1 Dec 2019 06:20:05 +0100
Subject: Issue #1308 - Create nsDisplayTableBackgroundColor to avoid display
 list collisions when processing the background color of a table.

This is effectively #146 Part 3c to go along with the other 2 there.

This resolves #1308.
---
 layout/base/nsDisplayList.cpp | 19 ++++++++++++++++---
 layout/base/nsDisplayList.h   | 21 +++++++++++++++++++++
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index 1579e6970..8a34d108f 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -2703,9 +2703,22 @@ nsDisplayBackgroundImage::AppendBackgroundItemsToTop(nsDisplayListBuilder* aBuil
                               bg->BottomLayer(), bgRect,
                               useWillPaintBorderOptimization);
     }
-    bgItemList.AppendNewToTop(
-        new (aBuilder) nsDisplayBackgroundColor(aBuilder, aFrame, bgRect, bg,
-                                                drawBackgroundColor ? color : NS_RGBA(0, 0, 0, 0)));
+    if (aSecondaryReferenceFrame) {
+      bgItemList.AppendNewToTop(
+          new (aBuilder) nsDisplayTableBackgroundColor(aBuilder,
+                                                       aSecondaryReferenceFrame,
+                                                       bgRect,
+                                                       bg,
+                                                       drawBackgroundColor ? color : NS_RGBA(0, 0, 0, 0),
+                                                       aFrame));
+    } else {
+      bgItemList.AppendNewToTop(
+          new (aBuilder) nsDisplayBackgroundColor(aBuilder,
+                                                  aFrame,
+                                                  bgRect,
+                                                  bg,
+                                                  drawBackgroundColor ? color : NS_RGBA(0, 0, 0, 0)));
+    }
   }
 
   if (isThemed) {
diff --git a/layout/base/nsDisplayList.h b/layout/base/nsDisplayList.h
index e9047b113..9cee7b517 100644
--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -3015,6 +3015,27 @@ protected:
   mozilla::gfx::Color mColor;
 };
 
+class nsDisplayTableBackgroundColor : public nsDisplayBackgroundColor
+{
+public:
+  nsDisplayTableBackgroundColor(nsDisplayListBuilder* aBuilder,
+                                nsIFrame* aFrame,
+                                const nsRect& aBackgroundRect,
+                                const nsStyleBackground* aBackgroundStyle,
+                                nscolor aColor,
+                                nsIFrame* aAncestorFrame)
+    : nsDisplayBackgroundColor(aBuilder, aFrame, aBackgroundRect, aBackgroundStyle, aColor)
+    , mTableType(GetTableTypeFromFrame(aAncestorFrame))
+  { }
+
+  virtual uint32_t GetPerFrameKey() override {
+    return (static_cast<uint8_t>(mTableType) << nsDisplayItem::TYPE_BITS) |
+            nsDisplayItem::GetPerFrameKey();
+  }
+protected:
+  TableType mTableType;
+};
+
 class nsDisplayClearBackground : public nsDisplayItem
 {
 public:
-- 
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