Remove render process and WebContents notifications from background printing.

chrome/browser/task_manager/tab_contents_resource_provider.cc

Index: chrome/browser/task_manager/tab_contents_resource_provider.cc
diff --git a/chrome/browser/task_manager/tab_contents_resource_provider.cc b/chrome/browser/task_manager/tab_contents_resource_provider.cc
index 9b79cc145eb5b15ee8ab87c60ca043c794053a81..8bf392ad5ac60d1dd3401c93b24dbe4b0d198a9f 100644
--- a/chrome/browser/task_manager/tab_contents_resource_provider.cc
+++ b/chrome/browser/task_manager/tab_contents_resource_provider.cc
@@ -249,9 +249,11 @@ void TabContentsResourceProvider::StartUpdating() {
   // Add all the pages being background printed.
   printing::BackgroundPrintingManager* printing_manager =
       g_browser_process->background_printing_manager();
-  for (printing::BackgroundPrintingManager::WebContentsSet::iterator i =
-           printing_manager->begin();
-       i != printing_manager->end(); ++i) {
+  std::set<content::WebContents*> printing_contents =
+      printing_manager->CurrentContentSet();
+  for (std::set<content::WebContents*>::iterator i =
+           printing_contents.begin();
+       i != printing_contents.end(); ++i) {
     Add(*i);
   }
 #endif