Add throbber and status text to WebBluetooth chooser UI on non-Mac desktops

chrome/browser/chooser_controller/chooser_controller.h

Index: chrome/browser/chooser_controller/chooser_controller.h
diff --git a/chrome/browser/chooser_controller/chooser_controller.h b/chrome/browser/chooser_controller/chooser_controller.h
index 7ed166fe8b1332c9ba822401fd03df3958b648af..d5d3583218d4708d1b18e544ce5ca3bac2119cb9 100644
--- a/chrome/browser/chooser_controller/chooser_controller.h
+++ b/chrome/browser/chooser_controller/chooser_controller.h
@@ -46,6 +46,12 @@ class ChooserController {
     // since the options have already been updated.
     virtual void OnOptionRemoved(size_t index) = 0;
 
+    // Called when the device adapter is turned on or off.
+    virtual void AdapterEnabled(bool enabled) = 0;

[msw, 2016/07/18 23:01:30]

nit: OnAdapterEnabledChanged? SetAdapterEnabled?

[juncai, 2016/07/19 20:42:45]

Done.

+
+    // Called when refreshing options is in progress or complete.
+    virtual void SetRefreshing(bool refreshing) = 0;

[msw, 2016/07/18 23:01:30]

nit: OnRefreshStateChanged?

[juncai, 2016/07/19 20:42:45]

Done.

+
    protected:
     virtual ~Observer() {}
   };
@@ -53,6 +59,9 @@ class ChooserController {
   // Returns the text to be displayed in the chooser title.
   base::string16 GetTitle() const;
 
+  // Returns the text to be displayed in the chooser when there is no option.

[Reilly Grant (use Gerrit), 2016/07/18 21:15:03]

s/is no option/are no options/

[juncai, 2016/07/19 20:42:45]

Done.

+  virtual base::string16 GetNoOptionsText() const = 0;
+
   // Returns the label for OK button.
   virtual base::string16 GetOkButtonLabel() const = 0;
 
@@ -64,6 +73,12 @@ class ChooserController {
   // The |index|th option string which is listed in the chooser.
   virtual base::string16 GetOption(size_t index) const = 0;
 
+  // Refresh the list of options.
+  virtual void RefreshOptions() = 0;
+
+  // 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.