content: Remove usage of NOTIFICATION_WEB_CONTENTS_DESTROYED from content

content/shell/shell.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 CONTENT_SHELL_SHELL_H_
 #define CONTENT_SHELL_SHELL_H_
 
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_piece.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_delegate.h"
+#include "content/public/browser/web_contents_observer.h"
 #include "ipc/ipc_channel.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 
 #if defined(TOOLKIT_GTK)
 #include <gtk/gtk.h>
 #include "ui/base/gtk/gtk_signal.h"
 
 typedef struct _GtkToolItem GtkToolItem;
 #elif defined(OS_ANDROID)
@@ skipping 15 matching lines @@
 
 class BrowserContext;
 class ShellDevToolsFrontend;
 class ShellJavaScriptDialogManager;
 class SiteInstance;
 class WebContents;
 
 // This represents one window of the Content Shell, i.e. all the UI including
 // buttons and url bar, as well as the web content area.
 class Shell : public WebContentsDelegate,
+              public WebContentsObserver,

[jochen (gone - plz use gerrit), 2013/05/10 19:53:33]

Shell shouldn't be a WebContentsObserver. Can you use a similar destruction
observer patterns as you use in WCI?

[Avi (use Gerrit), 2013/05/10 20:26:44]

What's your reasoning here?

[Paweł Hajdan Jr., 2013/05/13 20:15:31]

Done.

[Avi (use Gerrit), 2013/05/15 19:22:19]

Jochen: I will again ask why. Shell needs to observe a single WC, so why this
game of indirection and a proxy object?

[jochen (gone - plz use gerrit), 2013/05/21 12:09:44]

As I said, I don't remember the discussion we had about this exactly. In
general, Shell is a pretty lame object - a concept like this doesn't exist at
all in chrome/. It's a bit like a bastardized TabContents before we deleted it.

I think we should delete Shell all together (just like we did with TabContents).
Making it implement both WebContentsDelegate and WebContentsObserver will make
it just more difficult.

               public NotificationObserver {
  public:
   virtual ~Shell();
 
   void LoadURL(const GURL& url);
   void LoadURLForFrame(const GURL& url, const std::string& frame_name);
   void GoBackOrForward(int offset);
   void Reload();
   void Stop();
   void UpdateNavigationControls();
@@ skipping 74 matching lines @@
 #endif
   virtual bool AddMessageToConsole(WebContents* source,
                                    int32 level,
                                    const string16& message,
                                    int32 line_no,
                                    const string16& source_id) OVERRIDE;
   virtual void RendererUnresponsive(WebContents* source) OVERRIDE;
   virtual void ActivateContents(WebContents* contents) OVERRIDE;
   virtual void DeactivateContents(WebContents* contents) OVERRIDE;
 
+  // WebContentsObserver
+  virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE;
+
  private:
   enum UIControl {
     BACK_BUTTON,
     FORWARD_BUTTON,
     STOP_BUTTON
   };
 
   explicit Shell(WebContents* web_contents);
 
   // Helper to create a new Shell given a newly created WebContents.
@@ skipping 105 matching lines @@
   static base::Callback<void(Shell*)> shell_created_callback_;
 
   // True if the destructur of Shell should post a quit closure on the current
   // message loop if the destructed Shell object was the last one.
   static bool quit_message_loop_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_SHELL_H_