[omnibox] Break out SetCaretPos() method and enhance browser test

chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.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_COCOA_OMNIBOX_OMNIBOX_VIEW_MAC_H_
 #define CHROME_BROWSER_UI_COCOA_OMNIBOX_OMNIBOX_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
@@ skipping 48 matching lines @@
   void OpenMatch(const AutocompleteMatch& match,
                  WindowOpenDisposition disposition,
                  const GURL& alternate_nav_url,
                  const base::string16& pasted_text,
                  size_t selected_line) override;
   base::string16 GetText() const override;
   void SetWindowTextAndCaretPos(const base::string16& text,
                                 size_t caret_pos,
                                 bool update_popup,
                                 bool notify_text_changed) override;
+  void SetCaretPos(size_t caret_pos) override;
   void EnterKeywordModeForDefaultSearchProvider() override;
   bool IsSelectAll() const override;
   bool DeleteAtEndPressed() override;
   void GetSelectionBounds(base::string16::size_type* start,
                           base::string16::size_type* end) const override;
   void SelectAll(bool reversed) override;
   void RevertAll() override;
   void UpdatePopup() override;
   void CloseOmniboxPopup() override;
   void SetFocus() override;
@@ skipping 159 matching lines @@
   base::TimeTicks draw_rect_start_time_;
 
   // Temporary pointer to the attributed display string, stored as color and
   // other emphasis attributes are applied by the superclass.
   NSMutableAttributedString* attributing_display_string_;  // weak
 
   DISALLOW_COPY_AND_ASSIGN(OmniboxViewMac);
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_OMNIBOX_OMNIBOX_VIEW_MAC_H_