Add chrome side webusb permission UI code

chrome/browser/ui/website_settings/chooser_options.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_OPTIONS_H_
+#define CHROME_BROWSER_UI_WEBSITE_SETTINGS_CHOOSER_OPTIONS_H_
+
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/strings/string16.h"
+
+// Stores all the available chooser options, handle options initialization,

[Jeffrey Yasskin, 2015/12/05 01:13:53]

What is a "chooser option"?

[juncai, 2015/12/07 18:28:47]

chooser option is the item in the list that the chooser bubble shows for user to
select. For example, it can be usb/bluetooth device names which are listed on
the chooser bubble so that user can grant permission.

[Jeffrey Yasskin, 2015/12/07 23:57:54]

Include that in the comment, so folks can read the code to understand it,
instead of having to find this code review comment.

The class comment here should say how a subclass of ChooserOptions needs to
relate to a subclass of ChooserBubbleDelegate. For that matter, do you even need
two parallel class hierarchies? Could the ChooserBubbleDelegate have methods to
retrieve the options' display strings and a way to notify the ChooserTableModel?

+// option added/removed.
+class ChooserOptions {
+ public:
+  ChooserOptions() {}
+  virtual ~ChooserOptions() {}
+
+  class Observer {

[Jeffrey Yasskin, 2015/12/05 01:13:53]

How are subclasses supposed to use the Observer? BluetoothChooserOptions doesn't
appear to touch it, which surprises me.

[juncai, 2015/12/07 18:28:47]

It is the base class of ChooserTableModel:
https://codereview.chromium.org/1408193003/diff/530001/chrome/browser/ui/view...
and base class of ChooserBubbleUiCocoa:
https://codereview.chromium.org/1473393003/diff/60001/chrome/browser/ui/cocoa...
And ChooserTableModel/ChooserBubbleUiCocoa overrides
OnOptionsInitialized/OnOptionsAdded/OnOptionsRemoved to update the UI.

ChooserTableModel and ChooserBubbleUiCocoa are set as the observer of
ChooserOptions, when device added/removed, ChooserOptions calls observer's
OnOptionsInitialized/OnOptionsAdded/OnOptionsRemoved to notify it to update its
UI.

[Jeffrey Yasskin, 2015/12/07 23:57:54]

Again, write this sort of thing down in the class comments. Omit the specific
classes that implement this interface, since that'll change, but say what it
means to receive a call, and say when a ChooserOptions subclass needs to call
these functions. e.g. OnOptionRemoved might say "Called when GetOptions()[index]
is no longer present, and all later options have been moved earlier by 1 slot."
You should be clear about whether calling GetOptions()[index] from inside a call
to OnOption{Added,Removed} will see the added/removed string.

+   public:
+    virtual void OnOptionsInitialized() = 0;
+    virtual void OnOptionAdded(int index) = 0;
+    virtual void OnOptionRemoved(int index) = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  virtual const std::vector<base::string16>& GetOptions() const = 0;
+  virtual void Select(int index) = 0;
+
+  void set_observer(Observer* observer) { observer_ = observer; }
+  Observer* observer() const { return observer_; }
+
+ private:
+  Observer* observer_ = nullptr;
+  DISALLOW_COPY_AND_ASSIGN(ChooserOptions);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBSITE_SETTINGS_CHOOSER_OPTIONS_H_