Move histograms and supporting code that don't belong in content out.

chrome/browser/ui/tab_contents/core_tab_helper.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_TAB_CONTENTS_CORE_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_TAB_CONTENTS_CORE_TAB_HELPER_H_
 
+#include "base/time.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 class CoreTabHelperDelegate;
 
 // Per-tab class to handle functionality that is core to the operation of tabs.
 class CoreTabHelper : public content::WebContentsObserver,
                       public content::WebContentsUserData<CoreTabHelper> {
  public:
   virtual ~CoreTabHelper();
 
-  CoreTabHelperDelegate* delegate() const { return delegate_; }
-  void set_delegate(CoreTabHelperDelegate* d) { delegate_ = d; }
-
   // Initial title assigned to NavigationEntries from Navigate.
   static string16 GetDefaultTitle();
 
   // Returns a human-readable description the tab's loading state.
   string16 GetStatusText() const;
 
+  // Notification that tab closing has started.  This can be called multiple
+  // times, subsequent calls are ignored.
+  void OnCloseStarted();
+
+  // Notification that tab closing was cancelled. This can happen when a user
+  // cancels a window close via another tab's beforeunload dialog.
+  void OnCloseCanceled();
+
+  CoreTabHelperDelegate* delegate() const { return delegate_; }
+  void set_delegate(CoreTabHelperDelegate* d) { delegate_ = d; }
+
+  void set_new_tab_start_time(const base::TimeTicks& time) {
+    new_tab_start_time_ = time;
+  }
+
+  base::TimeTicks new_tab_start_time() const { return new_tab_start_time_; }
+
  private:
   explicit CoreTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<CoreTabHelper>;
 
   // content::WebContentsObserver overrides:
   virtual void WasShown() OVERRIDE;
+  virtual void WebContentsDestroyed(
+      content::WebContents* web_contents) OVERRIDE;
+  virtual void BeforeUnloadFired(const base::TimeTicks& proceed_time) OVERRIDE;
+  virtual void BeforeUnloadDialogCancelled() OVERRIDE;
 
   // Delegate for notifying our owner about stuff. Not owned by us.
   CoreTabHelperDelegate* delegate_;
 
+  // The time when we started to create the new tab page.  This time is from
+  // before we created this WebContents.
+  base::TimeTicks new_tab_start_time_;
+
+  // The time that we started to close this WebContents.
+  base::TimeTicks close_start_time_;
+
+  // The time when onbeforeunload ended.
+  base::TimeTicks before_unload_end_time_;
+
   DISALLOW_COPY_AND_ASSIGN(CoreTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_TAB_CONTENTS_CORE_TAB_HELPER_H_