Bug 301149 :hover is processed in Print Preview mode r+sr=roc

content/events/src/nsEventStateManager.cpp

@@ -4059,7 +4059,21 @@ nsEventStateManager::SetContentState(nsIContent *aContent, PRInt32 aState)
   nsCOMPtr<nsIContent> commonHoverAncestor, oldHover, newHover;
   if ((aState & NS_EVENT_STATE_HOVER) && (aContent != mHoverContent)) {
     oldHover = mHoverContent;
-    newHover = aContent;
+
+    if (!mPresContext || mPresContext->IsDynamic()) {
+      newHover = aContent;
+    } else {
+      nsIFrame *frame = mPresContext->PresShell()->GetPrimaryFrameFor(aContent);
+      if (nsLayoutUtils::IsViewportScrollbarFrame(frame)) {
+        // The scrollbars of viewport should not ignore the hover state.
+        // Because they are *not* the content of the web page.
+        newHover = aContent;
+      } else {
+        // All contents of the web page should ignore the hover state.
+        newHover = nsnull;
+      }
+    }
+
     commonHoverAncestor = FindCommonAncestor(mHoverContent, aContent);
     mHoverContent = aContent;
   }

layout/base/nsLayoutUtils.cpp

@@ -1062,3 +1062,26 @@ nsLayoutUtils::GetClosestCommonAncestorViaPlaceholders(nsIFrame* aFrame1,
   }
   return lastCommonFrame;
 }
+
+PRBool
+nsLayoutUtils::IsViewportScrollbarFrame(nsIFrame* aFrame)
+{
+  if (!aFrame)
+    return PR_FALSE;
+
+  nsIFrame* rootScrollFrame =
+    aFrame->GetPresContext()->PresShell()->GetRootScrollFrame();
+  if (!rootScrollFrame)
+    return PR_FALSE;
+
+  nsIScrollableFrame* rootScrollableFrame = nsnull;
+  CallQueryInterface(rootScrollFrame, &rootScrollableFrame);
+  NS_ASSERTION(rootScrollableFrame, "The root scorollable frame is null");
+
+  if (!IsProperAncestorFrame(rootScrollFrame, aFrame))
+    return PR_FALSE;
+
+  nsIFrame* rootScrolledFrame = rootScrollableFrame->GetScrolledFrame();
+  return !(rootScrolledFrame == aFrame ||
+           IsProperAncestorFrame(rootScrolledFrame, aFrame));
+}

layout/base/nsLayoutUtils.h

@@ -452,6 +452,15 @@ public:
   static nsIFrame*
   GetClosestCommonAncestorViaPlaceholders(nsIFrame* aFrame1, nsIFrame* aFrame2,
                                           nsIFrame* aKnownCommonAncestorHint);
+
+  /**
+   * Check whether aFrame is a part of the scrollbar or scrollcorner of
+   * the root content.
+   * @param aFrame the checking frame
+   * @return if TRUE, the frame is a part of the scrollbar or scrollcorner of
+   *         the root content.
+   */
+  static PRBool IsViewportScrollbarFrame(nsIFrame* aFrame);
 };
 
 #endif // nsLayoutUtils_h__