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

chrome/browser/chooser_controller/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_CHOOSER_CONTROLLER_H_
 #define CHROME_BROWSER_CHOOSER_CONTROLLER_CHOOSER_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "base/strings/string16.h"
 
@@ skipping 33 matching lines @@
     // since the options have already been updated.
     virtual void OnOptionRemoved(size_t index) = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
   // Returns the text to be displayed in the chooser title.
   base::string16 GetTitle() const;
 
+  // Returns the label for OK button.
+  virtual base::string16 GetOkButtonLabel() const = 0;
+
   // The number of options users can pick from. For example, it can be
   // the number of USB/Bluetooth device names which are listed in the
   // chooser so that users can grant permission.
   virtual size_t NumOptions() const = 0;
 
   // The |index|th option string which is listed in the chooser.
   virtual base::string16 GetOption(size_t index) const = 0;
 
   // These three functions are called just before this object is destroyed:
 
@@ skipping 15 matching lines @@
   Observer* observer() const { return observer_; }
 
  private:
   content::RenderFrameHost* owning_frame_;
   Observer* observer_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(ChooserController);
 };
 
 #endif  // CHROME_BROWSER_CHOOSER_CONTROLLER_CHOOSER_CONTROLLER_H_