Implement print preview tab controller.

chrome/browser/printing/print_preview_tab_controller.h

+// 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_PRINTING_PRINT_PREVIEW_TAB_CONTROLLER_H_
+#define CHROME_BROWSER_PRINTING_PRINT_PREVIEW_TAB_CONTROLLER_H_
+#pragma once
+
+#include <map>
+
+#include "base/ref_counted.h"
+#include "chrome/common/notification_observer.h"
+#include "chrome/common/notification_registrar.h"
+
+class Browser;
+class TabContents;
+
+namespace printing {
+
+// For print preview, a print preview (PP) tab should be linked with the
+// initiator tab that initiated the printing operation. If the tab initiates
+// a second printing operation while the first print preview tab is still open,
+// that PP tab should be focused/activated. There may be more than one PP tab
+// open. There is 1:1 relationship between PP tabs and initiating tabs. This
+// class manages PP tabs and initiator tabs.
+class PrintPreviewTabController
+  : public base::RefCounted<PrintPreviewTabController>,
+    public NotificationObserver {
+ public:
+  static PrintPreviewTabController* GetInstance();
+
+  PrintPreviewTabController();
+
+  virtual ~PrintPreviewTabController();
+
+  // Get/Create the print preview tab for initiator_tab.
+  // |browser_window_id| is used to identify |initiator_tab| browser window.
+  TabContents* GetOrCreatePreviewTab(
+      TabContents* initiator_tab, int browser_window_id);
+
+ private:
+  friend class base::RefCounted<PrintPreviewTabController>;
+
+  // Returns true if |tab| is a print preview tab.
+  bool IsPrintPreviewTab(TabContents* tab);
+
+  // Return the browser window with |browser_window_id|.
+  Browser* GetBrowserWindow(int browser_window_id);

[Lei Zhang, 2010/11/12 23:17:18]

This is a one line private method that's only called in one place. Remove?

[kmadhusu, 2010/11/13 00:05:59]

Removed.

+
+  // Return the initiator tab for |preview_tab| or return NULL.
+  TabContents* GetInitiatorTab(TabContents* preview_tab);
+
+  // Return preview tab for |initiator_tab| or return NULL.
+  TabContents* GetPreviewTab(TabContents* initiator_tab);
+
+  // Create a new print preview tab.
+  TabContents* CreatePrintPreviewTab(
+      TabContents* initiator_tab, int browser_window_id);
+
+  // Add |tab| notification(TAB_CONTENTS_DESTROYED & NAV_ENTRY_COMMITTED)

[Lei Zhang, 2010/11/12 23:48:40]

nit: Just combine the comments for Add and RemoveObservers:

// Add/Remove observers for notifications from |tab|.

[kmadhusu, 2010/11/13 00:05:59]

Done.

+  // observers.
+  void AddObservers(TabContents* tab);
+
+  // Remove |tab| notification(TAB_CONTENTS_DESTROYED & NAV_ENTRY_COMMITTED)
+  // observers.
+  void RemoveObservers(TabContents* tab);
+
+  // Notification observer implementation.
+  virtual void Observe(NotificationType type,

[Lei Zhang, 2010/11/12 23:48:40]

this needs to be public.

[kmadhusu, 2010/11/13 00:05:59]

Done.

+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+  // Erase the map entry for |initiator_tab|.
+  void EraseMapEntry(TabContents* initiator_tab);

[Lei Zhang, 2010/11/12 23:48:40]

again, why have a private, one line method that's only called once?

[kmadhusu, 2010/11/13 00:05:59]

Removed.

+
+  // 1:1 relationship between initiator tab and print preview tab.

[Lei Zhang, 2010/11/12 23:17:18]

You should state which type of tabs is the key and which is the value. It sounds
like key = initiator here, but it's actually PP.

[kmadhusu, 2010/11/13 00:05:59]

Done.

+  typedef std::map<TabContents*, TabContents*> PrintPreviewTabMap;
+  PrintPreviewTabMap preview_tab_map_;
+
+  // A registrar for listening for TAB_CONTENTS_DESTROYED notification.
+  NotificationRegistrar registrar_;
+
+  // Are we waiting for a new preview tab with NavigationType::NEW_PAGE? If so,
+  // do nothing in observer.
+  bool waiting_for_new_preview_page_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintPreviewTabController);
+};
+
+}  // namespace printing
+#endif  // CHROME_BROWSER_PRINTING_PRINT_PREVIEW_TAB_CONTROLLER_H_