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diff --git a/chrome/browser/tab_closeable_state_watcher.h b/chrome/browser/tab_closeable_state_watcher.h
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+++ b/chrome/browser/tab_closeable_state_watcher.h
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+// Copyright (c) 2010 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_TAB_CLOSEABLE_STATE_WATCHER_H_
+#define CHROME_BROWSER_TAB_CLOSEABLE_STATE_WATCHER_H_
+
+#include "base/basictypes.h"
+
+class Browser;
+
+// Base class for watching closeable state of tabs, which always returns true
+// to allow closing for all tabs and browsers.  Classes that desire otherwise
+// can inherit this class and override the methods as deemed appropriate to
+// allow or disallow tabs or browsers to be closed.
+
+class TabCloseableStateWatcher {
+ public:
+  TabCloseableStateWatcher() {}
+  virtual ~TabCloseableStateWatcher() {}
+
+  // Creates the appropriate TabCloseableStateWatcher.  The caller owns the
+  // returned object.
+  static TabCloseableStateWatcher* Create();
+
+  // Called from Browser::CanCloseTab which overrides TabStripModelDelegate::
+  // CanCloseTab, and returns true if tab of browser is closeable.
+  // Browser::CanCloseTab is in turn called by Browser, TabStripModel and
+  // BrowserTabStripController when:
+  // - rendering tab to determine if close button should be drawn
+  // - setting up tab's context menu to determine if "Close tab" should
+  //   should be enabled
+  // - determining if accelerator keys to close tab should be processed
+  virtual bool CanCloseTab(const Browser* browser) const {
+    return true;
+  }
+
+  // Called from Browser::IsClosingPermitted which is in turn called from
+  // Browser::ShouldCloseWindow to check if |browser| can be closed.
+  virtual bool CanCloseBrowser(Browser* browser) {
+    return true;
+  }
+
+  // Called from Browser::CancelWindowClose when closing of window is canceled.
+  // Watcher is potentially interested in this, especially when the closing of
+  // window was initiated by application exiting.
+  virtual void OnWindowCloseCanceled(Browser* browser) {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TabCloseableStateWatcher);
+};
+
+#endif  // CHROME_BROWSER_TAB_CLOSEABLE_STATE_WATCHER_H_