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

components/omnibox/browser/omnibox_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.
 
 // This file defines the interface class OmniboxView.  Each toolkit will
 // implement the edit view differently, so that code is inherently platform
 // specific.  However, the OmniboxEditModel needs to do some communication with
 // the view.  Since the model is shared between platforms, we need to define an
 // interface that all view implementations will share.
 
@@ skipping 86 matching lines @@
   virtual void SetUserText(const base::string16& text,
                            bool update_popup);
 
   // Sets the window text and the caret position. |notify_text_changed| is true
   // if the model should be notified of the change.
   virtual void SetWindowTextAndCaretPos(const base::string16& text,
                                         size_t caret_pos,
                                         bool update_popup,
                                         bool notify_text_changed) = 0;
 
+  // Sets the caret position. Removes any selection. Will not put caret
+  // past the current text.

[Peter Kasting, 2017/05/18 18:38:34]

Nit: This last sentence isn't perfectly clear about whether requests to do this
will be clamped or no-oped, so I'd instead say "Clamps the requested caret
position to the length of the current text."

[Kevin Bailey, 2017/05/18 19:48:17]

Done. ("Removes..." probably isn't necessary. Let me know if it clutters the
comment.)

+  virtual void SetCaretPos(size_t caret_pos) = 0;
+
   // Transitions the user into keyword mode with their default search provider,
   // preserving and selecting the user's text if they already typed in a query.
   virtual void EnterKeywordModeForDefaultSearchProvider() = 0;
 
   // Returns true if all text is selected or there is no text at all.
   virtual bool IsSelectAll() const = 0;
 
   // Returns true if the user deleted the suggested text.
   virtual bool DeleteAtEndPressed() = 0;
 
@@ skipping 165 matching lines @@
   friend class OmniboxViewMacTest;
 
   // |model_| can be NULL in tests.
   std::unique_ptr<OmniboxEditModel> model_;
   OmniboxEditController* controller_;
 
   DISALLOW_COPY_AND_ASSIGN(OmniboxView);
 };
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_OMNIBOX_VIEW_H_