Bug 258006 Mouse-wheel scroll events does not propagate to viewport from fixed pos. elements r+sr=roc

content/events/src/nsEventStateManager.cpp

@@ -1644,6 +1644,18 @@ ShouldScrollRootView(nsPresContext* aPresContext)
   return (aPresContext->Type() == nsPresContext::eContext_PrintPreview);
 }
 
+static nsIFrame*
+GetParentFrameToScroll(nsPresContext* aPresContext, nsIFrame* aFrame)
+{
+  if (!aPresContext || !aFrame)
+    return nsnull;
+
+  if (aFrame->GetStyleDisplay()->mPosition == NS_STYLE_POSITION_FIXED)
+    return aPresContext->GetPresShell()->GetRootScrollFrame();
+
+  return aFrame->GetParent();
+}
+
 nsresult
 nsEventStateManager::DoScrollText(nsPresContext* aPresContext,
                                   nsIFrame* aTargetFrame,
@@ -1750,7 +1762,8 @@ nsEventStateManager::DoScrollText(nsPresContext* aPresContext,
   nsIFrame* scrollFrame = aTargetFrame;
   PRBool passToParent = !scrollRootView;
 
-  for( ; scrollFrame && passToParent; scrollFrame = scrollFrame->GetParent()) {
+  for (; scrollFrame && passToParent;
+       scrollFrame = GetParentFrameToScroll(aPresContext, scrollFrame)) {
     // Check whether the frame wants to provide us with a scrollable view.
     scrollView = nsnull;
     nsCOMPtr<nsIScrollableViewProvider> svp = do_QueryInterface(scrollFrame);

layout/base/nsIPresShell.h

@@ -93,8 +93,8 @@ class nsCSSFrameConstructor;
 class nsISelection;
 
 #define NS_IPRESSHELL_IID     \
-{ 0x775a6c25, 0x326f, 0x4a99, \
- { 0xbb, 0x9d, 0x65, 0xdf, 0x15, 0xb3, 0x06, 0xa3 } }
+{ 0xcd6d6c1d, 0x4180, 0x432a, \
+ { 0x83, 0xbb, 0x1f, 0xc6, 0x50, 0xd2, 0x11, 0xa7 } }
 
 // Constants uses for ScrollFrameIntoView() function
 #define NS_PRESSHELL_SCROLL_TOP      0
@@ -291,6 +291,11 @@ public:
    */
   virtual NS_HIDDEN_(nsIFrame*) GetRootFrame() const;
 
+  /*
+   * Get root scroll frame from FrameManager()->GetRootFrame().
+   */
+  nsIFrame* GetRootScrollFrame() const;
+
   /**
    * Returns the page sequence frame associated with the frame hierarchy.
    * Returns NULL if not a paginated view.

layout/base/nsPresShell.cpp

@@ -2658,19 +2658,6 @@ static void CheckForFocus(nsPIDOMWindow* aOurWindow,
   aFocusController->SetFocusedWindow(ourWin);
 }
 
-static nsIFrame*
-GetRootScrollFrame(nsIFrame* aRootFrame) {
-  // Ensure root frame is a viewport frame
-  if (aRootFrame && nsLayoutAtoms::viewportFrame == aRootFrame->GetType()) {
-    nsIFrame* theFrame = aRootFrame->GetFirstChild(nsnull);
-    if (theFrame && nsLayoutAtoms::scrollFrame == theFrame->GetType()) {
-      return theFrame;
-    }
-  }
-
-  return nsnull;
-}
-
 NS_IMETHODIMP
 PresShell::GetDidInitialReflow(PRBool *aDidInitialReflow)
 {
@@ -3409,6 +3396,19 @@ nsIPresShell::GetRootFrame() const
   return FrameManager()->GetRootFrame();
 }
 
+nsIFrame*
+nsIPresShell::GetRootScrollFrame() const
+{
+  nsIFrame* rootFrame = FrameManager()->GetRootFrame();
+  // Ensure root frame is a viewport frame
+  if (!rootFrame || nsLayoutAtoms::viewportFrame != rootFrame->GetType())
+    return nsnull;
+  nsIFrame* theFrame = rootFrame->GetFirstChild(nsnull);
+  if (!theFrame || nsLayoutAtoms::scrollFrame != theFrame->GetType())
+    return nsnull;
+  return theFrame;
+}
+
 NS_IMETHODIMP
 PresShell::GetPageSequenceFrame(nsIPageSequenceFrame** aResult) const
 {
@@ -3469,7 +3469,6 @@ PresShell::EndLoad(nsIDocument *aDocument)
 {
 
   // Restore frame state for the root scroll frame
-  nsIFrame* rootFrame = FrameManager()->GetRootFrame();
   nsCOMPtr<nsILayoutHistoryState> historyState =
     aDocument->GetLayoutHistoryState();
   // Make sure we don't reenter reflow via the sync paint that happens while
@@ -3478,8 +3477,8 @@ PresShell::EndLoad(nsIDocument *aDocument)
   // it'll get all confused.
   ++mChangeNestCount;
 
-  if (rootFrame && historyState) {
-    nsIFrame* scrollFrame = GetRootScrollFrame(rootFrame);
+  if (historyState) {
+    nsIFrame* scrollFrame = GetRootScrollFrame();
     if (scrollFrame) {
       nsIScrollableFrame* scrollableFrame;
       CallQueryInterface(scrollFrame, &scrollableFrame);
@@ -4545,7 +4544,7 @@ PresShell::CaptureHistoryState(nsILayoutHistoryState** aState, PRBool aLeavingPa
   // As the scroll position is 0 and this will cause us to loose
   // our previously saved place!
   if (aLeavingPage) {
-    nsIFrame* scrollFrame = GetRootScrollFrame(rootFrame);
+    nsIFrame* scrollFrame = GetRootScrollFrame();
     if (scrollFrame) {
       FrameManager()->CaptureFrameStateFor(scrollFrame, historyState,
                                            nsIStatefulFrame::eDocumentScrollState);