From 93aa7aad04bb81c753ffa4585d4198b53bbf4def Mon Sep 17 00:00:00 2001
From: "Carsten \"Tomcat\" Book" <cbook@mozilla.com>
Date: Tue, 15 Jul 2014 10:30:21 +0200
Subject: [PATCH] Backed out changeset 032ba47c6684 (bug 1022612)

---
 layout/base/FrameLayerBuilder.cpp |  1 +
 layout/base/nsDisplayList.cpp     |  3 +++
 layout/base/nsDisplayList.h       | 26 ++++++++++++++++++++++----
 layout/base/nsLayoutDebugger.cpp  |  5 ++++-
 4 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/layout/base/FrameLayerBuilder.cpp b/layout/base/FrameLayerBuilder.cpp
index e6dc2676dc2..1c76e00d268 100644
--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -2735,6 +2735,7 @@ ContainerState::ProcessDisplayItems(nsDisplayList* aList,
   }
 
   aList->AppendToTop(&savedItems);
+  aList->SetDidComputeVisibility();
 }
 
 void
diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index 8031bf5e389..adc19bf694d 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -1221,6 +1221,9 @@ nsDisplayList::ComputeVisibilityForSublist(nsDisplayListBuilder* aBuilder,
 
   mIsOpaque = !aVisibleRegion->Intersects(mVisibleRect);
   mForceTransparentSurface = forceTransparentSurface;
+#if defined(DEBUG) || defined(MOZ_DUMP_PAINTING)
+  mDidComputeVisibility = true;
+#endif
   return anyVisible;
 }
 
diff --git a/layout/base/nsDisplayList.h b/layout/base/nsDisplayList.h
index 5af19316ea3..d346b41ca38 100644
--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -1425,12 +1425,14 @@ public:
   /**
    * Create an empty list.
    */
-  nsDisplayList()
-    : mIsOpaque(false)
-    , mForceTransparentSurface(false)
+  nsDisplayList() :
+    mIsOpaque(false)
   {
     mTop = &mSentinel;
     mSentinel.mAbove = nullptr;
+#if defined(DEBUG) || defined(MOZ_DUMP_PAINTING)
+    mDidComputeVisibility = false;
+#endif
   }
   ~nsDisplayList() {
     if (mSentinel.mAbove) {
@@ -1616,13 +1618,16 @@ public:
    * empty, i.e. everything visible in this list is opaque.
    */
   bool IsOpaque() const {
+    NS_ASSERTION(mDidComputeVisibility, "Need to have called ComputeVisibility");
     return mIsOpaque;
   }
 
   /**
-   * Returns true if any display item requires the surface to be transparent.
+   * Returns true if during ComputeVisibility any display item
+   * set the surface to be transparent.
    */
   bool NeedsTransparentSurface() const {
+    NS_ASSERTION(mDidComputeVisibility, "Need to have called ComputeVisibility");
     return mForceTransparentSurface;
   }
   /**
@@ -1681,6 +1686,16 @@ public:
                nsDisplayItem::HitTestState* aState,
                nsTArray<nsIFrame*> *aOutFrames) const;
 
+#if defined(DEBUG) || defined(MOZ_DUMP_PAINTING)
+  bool DidComputeVisibility() const { return mDidComputeVisibility; }
+#endif
+
+  void SetDidComputeVisibility()
+  {
+#if defined(DEBUG) || defined(MOZ_DUMP_PAINTING)
+    mDidComputeVisibility = true;
+#endif
+  }
   void SetIsOpaque()
   {
     mIsOpaque = true;
@@ -1712,6 +1727,9 @@ private:
   // This is set to true by ComputeVisibility if any display item in this
   // list needs to force the surface containing this list to be transparent.
   bool mForceTransparentSurface;
+#if defined(DEBUG) || defined(MOZ_DUMP_PAINTING)
+  bool mDidComputeVisibility;
+#endif
 };
 
 /**
diff --git a/layout/base/nsLayoutDebugger.cpp b/layout/base/nsLayoutDebugger.cpp
index 1096ef4cca8..ff7cb9119b8 100644
--- a/layout/base/nsLayoutDebugger.cpp
+++ b/layout/base/nsLayoutDebugger.cpp
@@ -154,7 +154,10 @@ PrintDisplayItemTo(nsDisplayListBuilder* aBuilder, nsDisplayItem* aItem,
   nsRect component = aItem->GetComponentAlphaBounds(aBuilder);
   nsDisplayList* list = aItem->GetChildren();
   const DisplayItemClip& clip = aItem->GetClip();
-  nsRegion opaque = aItem->GetOpaqueRegion(aBuilder, &snap);
+  nsRegion opaque;
+  if (!list || list->DidComputeVisibility()) {
+    opaque = aItem->GetOpaqueRegion(aBuilder, &snap);
+  }
   if (aDumpHtml && aItem->Painted()) {
     nsCString string(aItem->Name());
     string.Append('-');