Add a help bubble pointing to the omnibox when installing an extension with

chrome/browser/gtk/location_bar_view_gtk.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_GTK_LOCATION_BAR_VIEW_GTK_H_
 #define CHROME_BROWSER_GTK_LOCATION_BAR_VIEW_GTK_H_
 #pragma once
 
 #include <gtk/gtk.h>
 
@@ skipping 43 matching lines @@
   void Init(bool popup_window_mode);
 
   void SetProfile(Profile* profile);
 
   // Returns the widget the caller should host.  You must call Init() first.
   GtkWidget* widget() { return hbox_.get(); }
 
   // Returns the widget the page info bubble should point to.
   GtkWidget* location_icon_widget() const { return location_icon_image_; }
 
+  // Returns the widget the extension installed bubble should point to.
+  GtkWidget* location_entry_widget() const { return entry_box_; }
+
   // Returns the current TabContents.
   TabContents* GetTabContents() const;
 
   // Sets |preview_enabled| for the PageActionViewGtk associated with this
   // |page_action|. If |preview_enabled| is true, the view will display the
   // page action's icon even though it has not been activated by the extension.
   // This is used by the ExtensionInstalledBubbleGtk to preview what the icon
   // will look like for the user upon installation of the extension.
   void SetPreviewEnabledPageAction(ExtensionAction *page_action,
                                    bool preview_enabled);
@@ skipping 348 matching lines @@
   // The last search keyword that was shown via the |tab_to_search_box_|.
   std::wstring last_keyword_;
 
   // True if we should update the instant controller when the edit text changes.
   bool update_instant_;
 
   DISALLOW_COPY_AND_ASSIGN(LocationBarViewGtk);
 };
 
 #endif  // CHROME_BROWSER_GTK_LOCATION_BAR_VIEW_GTK_H_