Change WebBluetooth chooser OK button's label to be "Pair"

chrome/browser/chooser_controller/mock_chooser_controller.h

 // Copyright 2016 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_CHOOSER_CONTROLLER_MOCK_CHOOSER_CONTROLLER_H_
 #define CHROME_BROWSER_CHOOSER_CONTROLLER_MOCK_CHOOSER_CONTROLLER_H_
 
 #include <vector>
 
 #include "base/macros.h"
 #include "chrome/browser/chooser_controller/chooser_controller.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 class MockChooserController : public ChooserController {
  public:
   explicit MockChooserController(content::RenderFrameHost* owner);
   ~MockChooserController() override;
 
   // ChooserController:
+  base::string16 GetOkButtonLabel() const override;
   size_t NumOptions() const override;
   base::string16 GetOption(size_t index) const override;
   MOCK_METHOD1(Select, void(size_t index));
   MOCK_METHOD0(Cancel, void());
   MOCK_METHOD0(Close, void());
   MOCK_CONST_METHOD0(OpenHelpCenterUrl, void());
 
   void OptionAdded(const base::string16 option_name);
   void OptionRemoved(const base::string16 option_name);
 
  private:
   std::vector<base::string16> option_names_;
 
   DISALLOW_COPY_AND_ASSIGN(MockChooserController);
 };
 
 #endif  // CHROME_BROWSER_CHOOSER_CONTROLLER_MOCK_CHOOSER_CONTROLLER_H_