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 is 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 is focused/activated. There may be more than one PP tab open. There is a
+// 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.

[James Hawkins, 2010/11/16 18:24:30]

|initiator_tab|

[kmadhusu, 2010/11/16 18:41:42]

Done.

+  // |browser_window_id| is the browser window containing |initiator_tab|.
+  TabContents* GetOrCreatePreviewTab(
+      TabContents* initiator_tab, int browser_window_id);
+
+  // Notification observer implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+ private:
+  friend class base::RefCounted<PrintPreviewTabController>;
+
+  // Returns true if |tab| is a print preview tab.
+  bool IsPrintPreviewTab(TabContents* tab);
+
+  // Returns initiator tab for |preview_tab| or NULL.

[James Hawkins, 2010/11/16 18:24:30]

or NULL when...?

[kmadhusu, 2010/11/16 18:41:42]

Done.

+  TabContents* GetInitiatorTab(TabContents* preview_tab);
+
+  // Returns preview tab for |tab| or NULL.

[James Hawkins, 2010/11/16 18:24:30]

or NULL when...?

[kmadhusu, 2010/11/16 18:41:42]

Done.

+  // Returns |tab| if |tab| is a preview tab.
+  TabContents* GetPrintPreviewForTab(TabContents* tab);
+
+  // Creates a new print preview tab.
+  TabContents* CreatePrintPreviewTab(
+      TabContents* initiator_tab, int browser_window_id);
+
+  // Adds/Removes observers for notifications from |tab|.
+  void AddObservers(TabContents* tab);
+  void RemoveObservers(TabContents* tab);
+
+  // 1:1 relationship between initiator tab and print preview tab.
+  // Key: Preview tab.
+  // Value: Initiator tab.
+  typedef std::map<TabContents*, TabContents*> PrintPreviewTabMap;
+  PrintPreviewTabMap preview_tab_map_;
+
+  // A registrar for listening for TAB_CONTENTS_DESTROYED notification.

[James Hawkins, 2010/11/16 18:24:30]

s/TAB_CONTENTS_DESTROYED //

"A registrar for listening for notifications."

^ Because it's easy to get out of date (it's already out of date).

[kmadhusu, 2010/11/16 18:41:42]

Done.

+  NotificationRegistrar registrar_;
+
+  // True if the controller is waiting for a new preview tab via
+  // NavigationType::NEW_PAGE.
+  bool waiting_for_new_preview_page_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintPreviewTabController);
+};
+
+}  // namespace printing
+
+#endif  // CHROME_BROWSER_PRINTING_PRINT_PREVIEW_TAB_CONTROLLER_H_