Don't unblock onload on the document if we no longer have a parser. Bug375051, r=mbkap, sr=sicking

content/base/src/nsContentSink.cpp

@@ -1350,6 +1350,11 @@ nsContentSink::DidBuildModelImpl(void)
 void
 nsContentSink::DropParserAndPerfHint(void)
 {
+  if (!mParser) {
+    // Make sure we don't unblock unload too many times
+    return;
+  }
+  
   // Ref. Bug 49115
   // Do this hack to make sure that the parser
   // doesn't get destroyed, accidently, before

content/html/document/src/nsHTMLContentSink.cpp

@@ -1872,6 +1872,7 @@ HTMLContentSink::DidBuildModel(void)
 NS_IMETHODIMP
 HTMLContentSink::SetParser(nsIParser* aParser)
 {
+  NS_PRECONDITION(aParser, "Should have a parser here!");
   mParser = aParser;
   return NS_OK;
 }

content/xml/document/src/nsXMLContentSink.cpp

@@ -449,6 +449,7 @@ nsXMLContentSink::WillResume(void)
 NS_IMETHODIMP
 nsXMLContentSink::SetParser(nsIParser* aParser)
 {
+  NS_PRECONDITION(aParser, "Should have a parser here!");
   mParser = aParser;
   return NS_OK;
 }