Add metrics to keep track of the tab activate/deactivate cycle

chrome/browser/extensions/api/tabs/tabs_event_router.cc

Index: chrome/browser/extensions/api/tabs/tabs_event_router.cc
diff --git a/chrome/browser/extensions/api/tabs/tabs_event_router.cc b/chrome/browser/extensions/api/tabs/tabs_event_router.cc
index 53ed84084150df99104d0e8bd1578787d42d4204..5b1acc5b2909f41bf1e72fb9aeaccf6760ae9239 100644
--- a/chrome/browser/extensions/api/tabs/tabs_event_router.cc
+++ b/chrome/browser/extensions/api/tabs/tabs_event_router.cc
@@ -217,7 +217,8 @@ void TabsEventRouter::TabCreatedAt(WebContents* contents,
   RegisterForTabNotifications(contents);
 }
 
-void TabsEventRouter::TabInsertedAt(WebContents* contents,
+void TabsEventRouter::TabInsertedAt(TabStripModel* tab_strip_model,
+                                    WebContents* contents,
                                     int index,
                                     bool active) {
   if (!GetTabEntry(contents)) {
@@ -506,7 +507,9 @@ void TabsEventRouter::TabReplacedAt(TabStripModel* tab_strip_model,
     RegisterForTabNotifications(new_contents);
 }
 
-void TabsEventRouter::TabPinnedStateChanged(WebContents* contents, int index) {
+void TabsEventRouter::TabPinnedStateChanged(TabStripModel* tab_strip_model,
+                                            WebContents* contents,
+                                            int index) {
   TabStripModel* tab_strip = NULL;
   int tab_index;