#114429, caret ignores a backspace on a line before a <HR>.

r=jfrancis, sr=kin

editor/libeditor/html/nsHTMLEditRules.cpp

@@ -6253,12 +6253,14 @@ nsHTMLEditRules::AdjustSelection(nsISelection *aSelection, nsIEditor::EDirection
   res = mHTMLEditor->GetPriorHTMLSibling(selNode, selOffset, address_of(nearNode));
   if (NS_FAILED(res)) return res;
   if (nearNode && (nsTextEditUtils::IsBreak(nearNode)
-                   || nsHTMLEditUtils::IsImage(nearNode)))
+                   || nsHTMLEditUtils::IsImage(nearNode)
+                   || nsHTMLEditUtils::IsHR(nearNode)))
     return NS_OK; // this is a good place for the caret to be
   res = mHTMLEditor->GetNextHTMLSibling(selNode, selOffset, address_of(nearNode));
   if (NS_FAILED(res)) return res;
   if (nearNode && (nsTextEditUtils::IsBreak(nearNode)
-                   || nsHTMLEditUtils::IsImage(nearNode)))
+                   || nsHTMLEditUtils::IsImage(nearNode)
+                   || nsHTMLEditUtils::IsHR(nearNode)))
     return NS_OK; // this is a good place for the caret to be
 
   // look for a nearby text node.

editor/libeditor/html/nsHTMLEditUtils.cpp

@@ -101,6 +101,16 @@ nsHTMLEditUtils::IsParagraph(nsIDOMNode *node)
 }
 
 
+///////////////////////////////////////////////////////////////////////////
+// IsHR: true if node an horizontal rule
+//                  
+PRBool 
+nsHTMLEditUtils::IsHR(nsIDOMNode *node)
+{
+  return nsTextEditUtils::NodeIsType(node, NS_LITERAL_STRING("hr"));
+}
+
+
 ///////////////////////////////////////////////////////////////////////////
 // IsListItem: true if node an html list item
 //                  

editor/libeditor/html/nsHTMLEditUtils.h

@@ -54,6 +54,7 @@ public:
   // from nsHTMLEditRules:
   static PRBool IsHeader(nsIDOMNode *aNode);
   static PRBool IsParagraph(nsIDOMNode *aNode);
+  static PRBool IsHR(nsIDOMNode *aNode);
   static PRBool IsListItem(nsIDOMNode *aNode);
   static PRBool IsTable(nsIDOMNode *aNode);
   static PRBool IsTableRow(nsIDOMNode *aNode);