Add message and Help Center link to the chooser UI

chrome/browser/ui/website_settings/chooser_bubble_delegate.h

 // Copyright 2015 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_WEBSITE_SETTINGS_CHOOSER_BUBBLE_DELEGATE_H_
 #define CHROME_BROWSER_UI_WEBSITE_SETTINGS_CHOOSER_BUBBLE_DELEGATE_H_
 
 #include <vector>
 
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "components/bubble/bubble_delegate.h"
 
 class Browser;
+class GURL;
 
 // Subclass ChooserBubbleDelegate to implement a chooser bubble, which has
 // some introductory text and a list of options that users can pick one of.
 // Create an instance of your subclass and pass it to
 // BubbleManager::ShowBubble() to show the bubble. Your subclass must define
 // the set of options users can pick from; the actions taken after users
 // select an item or press the 'Cancel' button or the bubble is closed.
 // You can also override GetName() to identify the bubble you define for
 // collecting metrics.
 // After Select/Cancel/Close is called, this object is destroyed and call back
 // into it is not allowed.
+// TODO(juncai): Change class name ChooserBubbleDelegate to
+// ChooserBubbleController since it better reflects its responsibilities and
+// clarifies the roles of this class.
+// https://crbug.com/588933
 class ChooserBubbleDelegate : public BubbleDelegate {
  public:
   explicit ChooserBubbleDelegate(content::RenderFrameHost* owner);
   ~ChooserBubbleDelegate() override;
 
   // Since the set of options can change while the UI is visible an
   // implementation should register an observer.
   class Observer {
    public:
     // Called after the options list is initialized for the first time.
     // OnOptionsInitialized should only be called once.
     virtual void OnOptionsInitialized() = 0;
 
     // Called after GetOption(index) has been added to the options and the
     // newly added option is the last element in the options list. Calling
     // GetOption(index) from inside a call to OnOptionAdded will see the
     // added string since the options have already been updated.
     virtual void OnOptionAdded(size_t index) = 0;
 
     // Called when GetOption(index) is no longer present, and all later
     // options have been moved earlier by 1 slot. Calling GetOption(index)
     // from inside a call to OnOptionRemoved will NOT see the removed string
     // since the options have already been updated.
     virtual void OnOptionRemoved(size_t index) = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
+  // Open help center URL.
+  void OpenHelpCenterUrl() const;
+
   // BubbleDelegate:
   std::string GetName() const override;
   scoped_ptr<BubbleUi> BuildBubbleUi() override;
   const content::RenderFrameHost* OwningFrame() const override;
 
   // 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 bubble so that users can grant permission.
   virtual size_t NumOptions() const = 0;
 
   // The |index|th option string which is listed in the chooser bubble.
   virtual const base::string16& GetOption(size_t index) 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;
 
   // Called when the user clicks outside the dialog or the dialog otherwise
   // closes without the user taking an explicit action.
   virtual void Close() = 0;
 
+  // Get help center URL.
+  virtual GURL GetHelpCenterUrl() const = 0;
+
   // Only one observer may be registered at a time.
   void set_observer(Observer* observer) { observer_ = observer; }
   Observer* observer() const { return observer_; }
 
  private:
   Browser* browser_;
   const content::RenderFrameHost* const owning_frame_;
   Observer* observer_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(ChooserBubbleDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBSITE_SETTINGS_CHOOSER_BUBBLE_DELEGATE_H_