Add help link when Bluetooth adapter is off for WebBluetooth chooser

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 78 matching lines @@
   // This function returns false by default.
   virtual bool IsConnected(size_t index) const;
 
   // Returns if the |index|th option is paired.
   // This function returns false by default.
   virtual bool IsPaired(size_t index) const;
 
   // Refresh the list of options.
   virtual void RefreshOptions() = 0;
 
+  // Provide help information when the adapter is off.
+  virtual void OpenAdapterOffHelpUrl() const;

[Jeffrey Yasskin, 2016/09/26 23:25:07]

Put this next to the other Open...Url() function. If we want to make it pure,
add a TODO to do that. If not, why not?

[juncai, 2016/09/28 22:45:42]

Since the WebUSB doesn't use this function, and in order to avoid unnecessary
changes to the WebUSB related code, here it is not pure virtual so that WebUSB
code doesn't need to implement it.

Done.

[Jeffrey Yasskin, 2016/09/28 23:12:23]

Sounds good, thanks.

+
   // Returns the status text to be shown in the chooser.
   virtual base::string16 GetStatus() const = 0;
 
   // These three functions are called just before this object is destroyed:
 
   // Called when the user selects the |index|th element from the dialog.
   virtual void Select(size_t index) = 0;
 
   // Called when the user presses the 'Cancel' button in the dialog.
   virtual void Cancel() = 0;
@@ skipping 12 matching lines @@
  private:
   content::RenderFrameHost* const owning_frame_;
   const int title_string_id_origin_;
   const int title_string_id_extension_;
   View* view_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(ChooserController);
 };
 
 #endif  // CHROME_BROWSER_CHOOSER_CONTROLLER_CHOOSER_CONTROLLER_H_