Added notification when user presses backspace to use new shortcut.

chrome/browser/ui/views/frame/browser_view.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 CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_VIEW_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_VIEW_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 13 matching lines @@
 #include "chrome/browser/ui/infobar_container_delegate.h"
 #include "chrome/browser/ui/signin_view_controller.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/views/exclusive_access_bubble_views_context.h"
 #include "chrome/browser/ui/views/extensions/extension_keybinding_registry_views.h"
 #include "chrome/browser/ui/views/frame/browser_frame.h"
 #include "chrome/browser/ui/views/frame/contents_web_view.h"
 #include "chrome/browser/ui/views/frame/immersive_mode_controller.h"
 #include "chrome/browser/ui/views/frame/web_contents_close_handler.h"
 #include "chrome/browser/ui/views/load_complete_listener.h"
+#include "chrome/browser/ui/views/new_back_shortcut_bubble.h"

[Peter Kasting, 2016/05/24 23:35:08]

Nit: I think you can just forward-declare the type in this header and then
#include this in the .cc file.

[Matt Giuca, 2016/05/26 04:37:35]

Done.

 #include "chrome/common/features.h"
 #include "components/omnibox/browser/omnibox_popup_model_observer.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/models/simple_menu_model.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/webview/unhandled_keyboard_event_handler.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/widget/widget_observer.h"
 #include "ui/views/window/client_view.h"
@@ skipping 238 matching lines @@
                        ExclusiveAccessBubbleType bubble_type,
                        bool with_toolbar) override;
   void ExitFullscreen() override;
   void UpdateExclusiveAccessExitBubbleContent(
       const GURL& url,
       ExclusiveAccessBubbleType bubble_type) override;
   void OnExclusiveAccessUserInput() override;
   bool ShouldHideUIForFullscreen() const override;
   bool IsFullscreen() const override;
   bool IsFullscreenBubbleVisible() const override;
+  void ShowNewBackShortcutBubble(bool forward) override;
   LocationBar* GetLocationBar() const override;
   void SetFocusToLocationBar(bool select_all) override;
   void UpdateReloadStopState(bool is_loading, bool force) override;
   void UpdateToolbar(content::WebContents* contents) override;
   void ResetToolbarTabState(content::WebContents* contents) override;
   void FocusToolbar() override;
   ToolbarActionsBar* GetToolbarActionsBar() override;
   void ToolbarSizeChanged(bool is_animating) override;
   void FocusAppMenu() override;
   void FocusBookmarksToolbar() override;
@@ skipping 359 matching lines @@
   // OnThemeChanged()).
   bool handling_theme_changed_;
 
   // True when in ProcessFullscreen(). The flag is used to avoid reentrance and
   // to ignore requests to layout while in ProcessFullscreen() to reduce
   // jankiness.
   bool in_process_fullscreen_;
 
   std::unique_ptr<ExclusiveAccessBubbleViews> exclusive_access_bubble_;
 
+  std::unique_ptr<NewBackShortcutBubble> new_back_shortcut_bubble_;
+
 #if defined(OS_WIN)
   // Helper class to listen for completion of first page load.
   std::unique_ptr<LoadCompleteListener> load_complete_listener_;
 
   // The custom JumpList for Windows 7.
   scoped_refptr<JumpList> jumplist_;
 #endif
 
   // The timer used to update frames for the Loading Animation.
   base::RepeatingTimer loading_animation_timer_;
@@ skipping 13 matching lines @@
   // The class that registers for keyboard shortcuts for extension commands.
   std::unique_ptr<ExtensionKeybindingRegistryViews>
       extension_keybinding_registry_;
 
   mutable base::WeakPtrFactory<BrowserView> activate_modal_dialog_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_VIEW_H_