Bug 841192. Part 16: Take plugin's own clipping into account when computing the region for its window. Make SortByContentOrder handle cases where display items in the same list come from different documents. r=mattwoodrow

--HG--
extra : rebase_source : f39deb6250c7aef71d6cd3a62df43785a3bfc7b1

layout/base/nsDisplayList.cpp

@@ -1395,18 +1395,47 @@ static void Sort(nsDisplayList* aList, int32_t aCount, nsDisplayList::SortLEQ aC
   }
 }
 
+static nsIContent* FindContentInDocument(nsIContent* aContent, nsIDocument* aDoc) {
+  nsIContent* c = aContent;
+  for (;;) {
+    nsIDocument* d = c->OwnerDoc();
+    if (d == aDoc) {
+      return c;
+    }
+    nsIDocument* parentDoc = d->GetParentDocument();
+    if (!parentDoc) {
+      return nullptr;
+    }
+    c = parentDoc->FindContentForSubDocument(d);
+    if (!c) {
+      NS_ERROR("No content for subdocument?");
+      return nullptr;
+    }
+  }
+}
+
 static bool IsContentLEQ(nsDisplayItem* aItem1, nsDisplayItem* aItem2,
-                           void* aClosure) {
-  // These GetUnderlyingFrame calls return non-null because we're only used
-  // in sorting
-  return nsLayoutUtils::CompareTreePosition(
-      aItem1->GetUnderlyingFrame()->GetContent(),
-      aItem2->GetUnderlyingFrame()->GetContent(),
-      static_cast<nsIContent*>(aClosure)) <= 0;
+                         void* aClosure) {
+  nsIContent* commonAncestor = static_cast<nsIContent*>(aClosure);
+  // It's possible that the nsIContent for aItem1 or aItem2 is in a subdocument
+  // of commonAncestor, because display items for subdocuments have been
+  // mixed into the same list. Ensure that we're looking at content
+  // in commonAncestor's document.
+  nsIDocument* commonAncestorDoc = commonAncestor->OwnerDoc();
+  nsIContent* content1 = FindContentInDocument(aItem1->GetUnderlyingFrame()->GetContent(),
+                                               commonAncestorDoc);
+  nsIContent* content2 = FindContentInDocument(aItem2->GetUnderlyingFrame()->GetContent(),
+                                               commonAncestorDoc);
+  if (!content1 || !content2) {
+    NS_ERROR("Document trees are mixed up!");
+    // Something weird going on
+    return true;
+  }
+  return nsLayoutUtils::CompareTreePosition(content1, content2, commonAncestor) <= 0;
 }
 
 static bool IsZOrderLEQ(nsDisplayItem* aItem1, nsDisplayItem* aItem2,
-                          void* aClosure) {
+                        void* aClosure) {
   // These GetUnderlyingFrame calls return non-null because we're only used
   // in sorting.  Note that we can't just take the difference of the two
   // z-indices here, because that might overflow a 32-bit int.

layout/generic/nsFrame.cpp

@@ -1887,7 +1887,13 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
   // might have placed child outline items between its own outline items.
   // The element's outline items need to all come before any child outline
   // items.
-  set.Outlines()->SortByContentOrder(aBuilder, GetContent());
+  nsIContent* content = GetContent();
+  if (!content) {
+    content = PresContext()->Document()->GetRootElement();
+  }
+  if (content) {
+    set.Outlines()->SortByContentOrder(aBuilder, content);
+  }
 #ifdef DEBUG
   DisplayDebugBorders(aBuilder, this, set);
 #endif

layout/generic/nsObjectFrame.cpp

@@ -1058,9 +1058,8 @@ nsDisplayPlugin::ComputeVisibility(nsDisplayListBuilder* aBuilder,
         ReferenceFrame()->PresContext()->AppUnitsPerDevPixel();
       f->mNextConfigurationBounds = rAncestor.ToNearestPixels(appUnitsPerDevPixel);
 
-      bool snap;
       nsRegion visibleRegion;
-      visibleRegion.And(*aVisibleRegion, GetBounds(aBuilder, &snap));
+      visibleRegion.And(*aVisibleRegion, GetClippedBounds(aBuilder));
       // Make visibleRegion relative to f
       visibleRegion.MoveBy(-ToReferenceFrame());