diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 1f5f92152acb..f5d61ba7ae95 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -834,7 +834,6 @@ public:
                                                         nsIDOMEvent* aEvent,
                                                         nsEventStatus* aStatus);
   NS_IMETHOD ResizeReflow(nsIView *aView, nscoord aWidth, nscoord aHeight);
-  NS_IMETHOD_(PRBool) IsVisible();
   NS_IMETHOD_(PRBool) ShouldIgnoreInvalidation();
   NS_IMETHOD_(void) WillPaint(PRBool aWillSendDidPaint);
   NS_IMETHOD_(void) DidPaint();
@@ -7181,18 +7180,6 @@ PresShell::ResizeReflow(nsIView *aView, nscoord aWidth, nscoord aHeight)
   return ResizeReflow(aWidth, aHeight);
 }
 
-NS_IMETHODIMP_(PRBool)
-PresShell::IsVisible()
-{
-  nsCOMPtr<nsISupports> container = mPresContext->GetContainer();
-  nsCOMPtr<nsIBaseWindow> bw = do_QueryInterface(container);
-  if (!bw)
-    return PR_FALSE;
-  PRBool res = PR_TRUE;
-  bw->GetVisibility(&res);
-  return res;
-}
-
 NS_IMETHODIMP_(PRBool)
 PresShell::ShouldIgnoreInvalidation()
 {
diff --git a/view/public/nsIViewObserver.h b/view/public/nsIViewObserver.h
index 706768cf552e..0d944adac69e 100644
--- a/view/public/nsIViewObserver.h
+++ b/view/public/nsIViewObserver.h
@@ -47,8 +47,8 @@ class nsIRenderingContext;
 class nsGUIEvent;
 
 #define NS_IVIEWOBSERVER_IID  \
-  { 0x6af699da, 0x8bfe, 0x43c9, \
-    { 0xae, 0xc1, 0x76, 0x1b, 0x03, 0x62, 0x8d, 0x64 } }
+  { 0x4d467c73, 0xb6a9, 0x462a, \
+    { 0x90, 0x25, 0x80, 0xd9, 0x42, 0xbc, 0xcc, 0xb5 } }
 
 class nsIViewObserver : public nsISupports
 {
@@ -107,12 +107,6 @@ public:
    */
   NS_IMETHOD ResizeReflow(nsIView * aView, nscoord aWidth, nscoord aHeight) = 0;
 
-  /**
-   * Hack to find out if the view observer is itself visible, in lieu
-   * of having the view trees linked.
-   */
-  NS_IMETHOD_(PRBool) IsVisible() = 0;
-
   /**
    * Returns true if the view observer wants to drop all invalidation right now
    * because painting is suppressed. It will invalidate everything when it
diff --git a/view/src/nsViewManager.cpp b/view/src/nsViewManager.cpp
index 84660fb4c243..ad40891d7bb2 100644
--- a/view/src/nsViewManager.cpp
+++ b/view/src/nsViewManager.cpp
@@ -100,18 +100,6 @@ public:
 
 //-------------- End Invalidate Event Definition ---------------------------
 
-static PRBool IsViewVisible(nsView *aView)
-{
-  if (!aView->IsEffectivelyVisible())
-    return PR_FALSE;
-
-  // Find out if the root view is visible by asking the view observer
-  // (this won't be needed anymore if we link view trees across chrome /
-  // content boundaries in DocumentViewerImpl::MakeWindow).
-  nsIViewObserver* vo = aView->GetViewManager()->GetViewObserver();
-  return vo && vo->IsVisible();
-}
-
 void
 nsViewManager::PostInvalidateEvent()
 {
@@ -324,7 +312,7 @@ void nsViewManager::DoSetWindowDimensions(nscoord aWidth, nscoord aHeight)
 NS_IMETHODIMP nsViewManager::SetWindowDimensions(nscoord aWidth, nscoord aHeight)
 {
   if (mRootView) {
-    if (IsViewVisible(mRootView)) {
+    if (mRootView->IsEffectivelyVisible()) {
       mDelayedResize.SizeTo(NSCOORD_NONE, NSCOORD_NONE);
       DoSetWindowDimensions(aWidth, aHeight);
     } else {
@@ -879,7 +867,7 @@ NS_IMETHODIMP nsViewManager::DispatchEvent(nsGUIEvent *aEvent,
                       ? vm->mRootView->GetParent()->GetViewManager()
                       : nsnull) {
             if (vm->mDelayedResize != nsSize(NSCOORD_NONE, NSCOORD_NONE) &&
-                IsViewVisible(vm->mRootView)) {
+                vm->mRootView->IsEffectivelyVisible()) {
               vm->FlushDelayedResize(PR_TRUE);
 
               // Paint later.
@@ -894,7 +882,7 @@ NS_IMETHODIMP nsViewManager::DispatchEvent(nsGUIEvent *aEvent,
           }
 
           if (!didResize) {
-            //NS_ASSERTION(IsViewVisible(view), "painting an invisible view");
+            //NS_ASSERTION(view->IsEffectivelyVisible(), "painting an invisible view");
 
             // Notify view observers that we're about to paint.
             // Make sure to not send WillPaint notifications while scrolling.