Add heuristics to limit showing of new backspace UI bubble.

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>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "chrome/browser/devtools/devtools_window.h"
 #include "chrome/browser/extensions/extension_commands_global_registry.h"
 #include "chrome/browser/extensions/extension_keybinding_registry.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/exclusive_access/exclusive_access_context.h"
 #include "chrome/browser/ui/infobar_container_delegate.h"
 #include "chrome/browser/ui/signin_view_controller.h"
@@ skipping 254 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;
+  void MaybeShowNewBackShortcutBubble(bool forward) override;
+  void HideNewBackShortcutBubble() 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 361 matching lines @@
   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_;
+  base::TimeTicks last_back_shortcut_press_time_;
 
 #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.
@@ skipping 14 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_