Add histograms that track how long it takes to open the new tab page.

chrome/browser/browser.cc

Index: chrome/browser/browser.cc
diff --git a/chrome/browser/browser.cc b/chrome/browser/browser.cc
index e0cc0478e8f873866da5d7e36ee40e25a0633081..122310199ae2dc4981049828c7ff055d1695308a 100644
--- a/chrome/browser/browser.cc
+++ b/chrome/browser/browser.cc
@@ -1512,8 +1512,14 @@ TabContents* Browser::AddBlankTab(bool foreground) {
 }
 
 TabContents* Browser::AddBlankTabAt(int index, bool foreground) {
-  return AddTabWithURL(GURL(chrome::kChromeUINewTabURL), GURL(),
-                       PageTransition::TYPED, foreground, index, false, NULL);
+  // Time new tab page creation time.  We keep track of the timing data in
+  // TabContents, but we want to include the time it takes to create the
+  // TabContents object too.
+  base::TimeTicks new_tab_start_time = base::TimeTicks::Now();
+  TabContents* tab_contents =  AddTabWithURL(GURL(chrome::kChromeUINewTabURL),
+      GURL(), PageTransition::TYPED, foreground, index, false, NULL);
+  tab_contents->set_new_tab_start_time(new_tab_start_time);
+  return tab_contents;
 }
 
 Browser* Browser::CreateNewStripWithContents(TabContents* detached_contents,