Bug 1031107 - Part 4: Union the display port dirty area in nsSubDocumentFrame. r=tn

layout/generic/nsGfxScrollFrame.cpp

@@ -2433,13 +2433,18 @@ ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
     // If we are a root scroll frame that has a display port we want to add
     // scrollbars, they will be children of the scrollable layer, but they get
     // adjusted by the APZC automatically.
-    bool addScrollBars = mIsRoot &&
-      nsLayoutUtils::GetDisplayPort(mOuter->GetContent()) &&
-      !aBuilder->IsForEventDelivery();
+    bool usingDisplayPort = nsLayoutUtils::GetDisplayPort(mOuter->GetContent());
+    bool addScrollBars = mIsRoot && usingDisplayPort && !aBuilder->IsForEventDelivery();
+
+    nsRect scrollbarDirty = aDirtyRect;
+    if (usingDisplayPort) {
+      // Make sure we include the scrollbars.
+      scrollbarDirty.Inflate(GetActualScrollbarSizes());
+    }
 
     if (addScrollBars) {
       // Add classic scrollbars.
-      AppendScrollPartsTo(aBuilder, aDirtyRect, aLists, createLayersForScrollbars,
+      AppendScrollPartsTo(aBuilder, scrollbarDirty, aLists, createLayersForScrollbars,
                           false);
     }
 
@@ -2451,23 +2456,13 @@ ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
 
     if (addScrollBars) {
       // Add overlay scrollbars.
-      AppendScrollPartsTo(aBuilder, aDirtyRect, aLists,
+      AppendScrollPartsTo(aBuilder, scrollbarDirty, aLists,
                           createLayersForScrollbars, true);
     }
 
     return;
   }
 
-  // Now display the scrollbars and scrollcorner. These parts are drawn
-  // in the border-background layer, on top of our own background and
-  // borders and underneath borders and backgrounds of later elements
-  // in the tree.
-  // Note that this does not apply for overlay scrollbars; those are drawn
-  // in the positioned-elements layer on top of everything else by the call
-  // to AppendScrollPartsTo(..., true) further down.
-  AppendScrollPartsTo(aBuilder, aDirtyRect, aLists, createLayersForScrollbars,
-                      false);
-
   // Overflow clipping can never clip frames outside our subtree, so there
   // is no need to worry about whether we are a moving frame that might clip
   // non-moving frames.
@@ -2514,6 +2509,22 @@ ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
     }
   }
 
+  nsRect scrollbarDirty = aDirtyRect;
+  if (usingDisplayport) {
+    // Make sure we include the scrollbars.
+    scrollbarDirty.Inflate(GetActualScrollbarSizes());
+  }
+
+  // Now display the scrollbars and scrollcorner. These parts are drawn
+  // in the border-background layer, on top of our own background and
+  // borders and underneath borders and backgrounds of later elements
+  // in the tree.
+  // Note that this does not apply for overlay scrollbars; those are drawn
+  // in the positioned-elements layer on top of everything else by the call
+  // to AppendScrollPartsTo(..., true) further down.
+  AppendScrollPartsTo(aBuilder, scrollbarDirty, aLists, createLayersForScrollbars,
+                      false);
+
   if (aBuilder->IsForImageVisibility()) {
     // We expand the dirty rect to catch images just outside of the scroll port.
     // We use the dirty rect instead of the whole scroll port to prevent
@@ -2650,7 +2661,7 @@ ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
     }
   }
   // Now display overlay scrollbars and the resizer, if we have one.
-  AppendScrollPartsTo(aBuilder, aDirtyRect, scrolledContent,
+  AppendScrollPartsTo(aBuilder, scrollbarDirty, scrolledContent,
                       createLayersForScrollbars, true);
   scrolledContent.MoveTo(aLists);
 }

layout/generic/nsSubDocumentFrame.cpp

@@ -408,7 +408,8 @@ nsSubDocumentFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
           nsRect(nsPoint(0,0), nsLayoutUtils::CalculateCompositionSizeForFrame(rootScrollFrame)) :
           dirty.Intersect(nsRect(nsPoint(0,0), subdocRootFrame->GetSize()));
       nsRect displayPort;
-      if (nsLayoutUtils::GetOrMaybeCreateDisplayPort(
+      if (!aBuilder->IsForEventDelivery() &&
+          nsLayoutUtils::GetOrMaybeCreateDisplayPort(
             *aBuilder, rootScrollFrame, displayportBase, &displayPort)) {
         haveDisplayPort = true;
         dirty = displayPort;