Fix for bug 194738: Phoenix/Mozilla minimizes to toolbar then re-opens.

r=roc+moz
sr=bzbarsky

layout/generic/nsContainerFrame.cpp

@@ -778,14 +778,13 @@ nsContainerFrame::SyncFrameViewProperties(nsIPresContext*  aPresContext,
     if (NS_STYLE_VISIBILITY_COLLAPSE == vis->mVisible) {
       viewIsVisible = PR_FALSE;
     }
-    else if (NS_STYLE_VISIBILITY_HIDDEN == vis->mVisible) {
+    else if (NS_STYLE_VISIBILITY_HIDDEN == vis->mVisible &&
+             !aFrame->SupportsVisibilityHidden()) {
       // If it's a scrollable frame that can't hide its scrollbars,
       // hide the view. This means that child elements can't override
       // their parent's visibility, but it's not practical to leave it
       // visible in all cases because the scrollbars will be showing
-      if (!aFrame->SupportsVisibilityHidden()) {
-        viewIsVisible = PR_FALSE;
-      }
+      viewIsVisible = PR_FALSE;
     } else {
       // if the view is for a popup, don't show the view if the popup is closed
       nsCOMPtr<nsIWidget> widget;

layout/html/base/src/nsContainerFrame.cpp

@@ -778,14 +778,13 @@ nsContainerFrame::SyncFrameViewProperties(nsIPresContext*  aPresContext,
     if (NS_STYLE_VISIBILITY_COLLAPSE == vis->mVisible) {
       viewIsVisible = PR_FALSE;
     }
-    else if (NS_STYLE_VISIBILITY_HIDDEN == vis->mVisible) {
+    else if (NS_STYLE_VISIBILITY_HIDDEN == vis->mVisible &&
+             !aFrame->SupportsVisibilityHidden()) {
       // If it's a scrollable frame that can't hide its scrollbars,
       // hide the view. This means that child elements can't override
       // their parent's visibility, but it's not practical to leave it
       // visible in all cases because the scrollbars will be showing
-      if (!aFrame->SupportsVisibilityHidden()) {
-        viewIsVisible = PR_FALSE;
-      }
+      viewIsVisible = PR_FALSE;
     } else {
       // if the view is for a popup, don't show the view if the popup is closed
       nsCOMPtr<nsIWidget> widget;