Bug 111432 [FIRST] Mouse wheel scrolling doesn't work in print preview on page margin or on frame page r+sr=roc

content/events/src/nsEventStateManager.cpp

@@ -1639,6 +1639,12 @@ nsEventStateManager::DoScrollTextsize(nsIFrame *aTargetFrame,
     }
 }
 
+inline PRBool
+ShouldScrollRootView(nsPresContext* aPresContext)
+{
+  return (aPresContext->Type() == nsPresContext::eContext_PrintPreview);
+}
+
 nsresult
 nsEventStateManager::DoScrollText(nsPresContext* aPresContext,
                                   nsIFrame* aTargetFrame,
@@ -1647,6 +1653,38 @@ nsEventStateManager::DoScrollText(nsPresContext* aPresContext,
                                   PRBool aScrollHorizontal,
                                   PRBool aScrollPage)
 {
+  nsIScrollableView* scrollView = nsnull;
+  PRBool scrollRootView = ShouldScrollRootView(aPresContext);
+
+  if (scrollRootView) {
+    // Get root scroll view
+    nsIViewManager* vm = aPresContext->GetViewManager();
+    NS_ENSURE_TRUE(vm, NS_ERROR_FAILURE);
+    vm->GetRootScrollableView(&scrollView);
+    if (!scrollView) {
+      // We don't have root scrollable view in current document.
+      // Maybe, this is sub frame on Print Preview.
+      // Let's pass to parent document.
+      nsIFrame* newFrame = nsnull;
+      nsCOMPtr<nsPresContext> newPresContext = nsnull;
+      nsresult rv = GetParentScrollingView(aEvent, aPresContext, newFrame,
+                                           *getter_AddRefs(newPresContext));
+      NS_ENSURE_SUCCESS(rv, rv);
+      NS_ENSURE_TRUE(newFrame && newPresContext, NS_ERROR_FAILURE);
+      return DoScrollText(newPresContext, newFrame, aEvent, aNumLines,
+                          aScrollHorizontal, aScrollPage);
+    }
+    // find target frame that is root scrollable content
+    nsIFrame* targetFrame = aTargetFrame;
+    for ( ;targetFrame; targetFrame = targetFrame->GetParent()) {
+      nsCOMPtr<nsIScrollableViewProvider> svp = do_QueryInterface(targetFrame);
+      if (svp && scrollView == svp->GetScrollableView())
+        break;
+    }
+    NS_ENSURE_TRUE(targetFrame, NS_ERROR_FAILURE);
+    aTargetFrame = targetFrame;
+  }
+
   nsCOMPtr<nsIContent> targetContent = aTargetFrame->GetContent();
   if (!targetContent)
     GetFocusedContent(getter_AddRefs(targetContent));
@@ -1694,21 +1732,24 @@ nsEventStateManager::DoScrollText(nsPresContext* aPresContext,
       target->DispatchEvent(event, &defaultActionEnabled);
       if (!defaultActionEnabled)
         return NS_OK;
-      // Re-resolve |aTargetFrame| in case it was destroyed by the
-      // DOM event handler above, bug 257998.
-      aTargetFrame = aPresContext->GetPresShell()->GetPrimaryFrameFor(targetContent);
-      if (!aTargetFrame) {
-        // Without a frame we can't do the normal ancestor search for a view to scroll.
-        // Don't fall through to the "passToParent" code at the end because that will
-        // likely scroll the wrong view (in an enclosing document).
-        return NS_OK;
+      if (!scrollRootView) {
+        // Re-resolve |aTargetFrame| in case it was destroyed by the
+        // DOM event handler above, bug 257998.
+        aTargetFrame =
+          aPresContext->GetPresShell()->GetPrimaryFrameFor(targetContent);
+        if (!aTargetFrame) {
+          // Without a frame we can't do the normal ancestor search for a view
+          // to scroll. Don't fall through to the "passToParent" code at the end
+          // because that will likely scroll the wrong view (in an enclosing
+          // document).
+          return NS_OK;
+        }
       }
     }
   }
 
   nsIFrame* scrollFrame = aTargetFrame;
-  nsIScrollableView* scrollView = nsnull;
-  PRBool passToParent = PR_TRUE;
+  PRBool passToParent = !scrollRootView;
 
   for( ; scrollFrame && passToParent; scrollFrame = scrollFrame->GetParent()) {
     // Check whether the frame wants to provide us with a scrollable view.
@@ -1815,7 +1856,16 @@ nsEventStateManager::GetParentScrollingView(nsInputEvent *aEvent,
     return NS_OK;
   }
 
-  nsIPresShell *pPresShell = parentDoc->GetShellAt(0);
+  nsIPresShell *pPresShell = nsnull;
+  for (PRUint32 i = 0; i < parentDoc->GetNumberOfShells(); i++) {
+    nsIPresShell *tmpPresShell = parentDoc->GetShellAt(i);
+    NS_ENSURE_TRUE(tmpPresShell, NS_ERROR_FAILURE);
+    NS_ENSURE_TRUE(tmpPresShell->GetPresContext(), NS_ERROR_FAILURE);
+    if (tmpPresShell->GetPresContext()->Type() == aPresContext->Type()) {
+      pPresShell = tmpPresShell;
+      break;
+    }
+  }
   NS_ENSURE_TRUE(pPresShell, NS_ERROR_FAILURE);
 
   /* now find the content node in our parent docshell's document that