Fixed the issue shows keyword hint when omnibox loses its focus.

chrome/browser/ui/omnibox/chrome_omnibox_edit_controller.h

 // Copyright 2015 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_OMNIBOX_CHROME_OMNIBOX_EDIT_CONTROLLER_H_
 #define CHROME_BROWSER_UI_OMNIBOX_CHROME_OMNIBOX_EDIT_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "components/omnibox/browser/omnibox_edit_controller.h"
+#include "components/omnibox/common/omnibox_focus_state.h"
 
 class CommandUpdater;
 
 namespace content {
 class WebContents;
 }
 
 // Chrome-specific extension of the OmniboxEditController base class.
 class ChromeOmniboxEditController : public OmniboxEditController {
  public:
   // Returns the WebContents of the currently active tab.
   virtual content::WebContents* GetWebContents() = 0;
 
   // Called when the the controller should update itself without restoring any
   // tab state.
   virtual void UpdateWithoutTabRestore() = 0;
 
+  // Called when omnibox focus was changed.
+  virtual void OnFocusChanged(OmniboxFocusState state) = 0;
+
   CommandUpdater* command_updater() { return command_updater_; }
   const CommandUpdater* command_updater() const { return command_updater_; }
 
  protected:
   explicit ChromeOmniboxEditController(CommandUpdater* command_updater);
   ~ChromeOmniboxEditController() override;
 
  private:
   // OmniboxEditController:
   void OnAutocompleteAccept(const GURL& destination_url,
                             WindowOpenDisposition disposition,
                             ui::PageTransition transition,
                             AutocompleteMatchType::Type type) override;
   void OnInputInProgress(bool in_progress) override;
 
   CommandUpdater* command_updater_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeOmniboxEditController);
 };
 
 #endif  // CHROME_BROWSER_UI_OMNIBOX_CHROME_OMNIBOX_EDIT_CONTROLLER_H_