Fix and re-enable PrerenderTaskManager test

chrome/browser/prerender/prerender_browsertest.cc

Index: chrome/browser/prerender/prerender_browsertest.cc
diff --git a/chrome/browser/prerender/prerender_browsertest.cc b/chrome/browser/prerender/prerender_browsertest.cc
index de14f6de264b96883ff72ff176a02c6efff532ad..c08f997300cf1bcd67f8a57beed73972c218e2e2 100644
--- a/chrome/browser/prerender/prerender_browsertest.cc
+++ b/chrome/browser/prerender/prerender_browsertest.cc
@@ -1889,7 +1889,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest,
 }
 
 // See crbug.com/131836.
-IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, DISABLED_PrerenderTaskManager) {
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderTaskManager) {
   // Show the task manager. This populates the model.
   chrome::OpenTaskManager(current_browser());
   // Wait for the model of task manager to start.
@@ -1905,7 +1905,9 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, DISABLED_PrerenderTaskManager) {
   string16 prerender_title;
   int num_prerender_tabs = 0;
 
-  const TaskManagerModel* model = GetModel();
+  TaskManagerModel* model = GetModel();
+  // The task manager caches values. Force the titles to be fresh.
+  model->Refresh();
   for (int i = 0; i < model->ResourceCount(); ++i) {
     if (model->GetResourceWebContents(i)) {
       prerender_title = model->GetResourceTitle(i);
@@ -1923,6 +1925,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, DISABLED_PrerenderTaskManager) {
       l10n_util::GetStringFUTF16(IDS_TASK_MANAGER_TAB_PREFIX, string16());
   num_prerender_tabs = 0;
   int num_tabs_with_prerender_page_title = 0;
+  model->Refresh();
   for (int i = 0; i < model->ResourceCount(); ++i) {
     if (model->GetResourceWebContents(i)) {
       string16 tab_title = model->GetResourceTitle(i);