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..2622bb3fbc658022a386981aaed465bcd6de1508 100644
--- a/chrome/browser/chooser_controller/chooser_controller.h
+++ b/chrome/browser/chooser_controller/chooser_controller.h
@@ -46,6 +46,18 @@ class ChooserController {
     // since the options have already been updated.
     virtual void OnOptionRemoved(size_t index) = 0;
 
+    // Called when the device adapter is truned on.

[Reilly Grant (use Gerrit), 2016/07/15 21:55:20]

s/truned/turned/

[juncai, 2016/07/18 20:14:16]

Done.

+    virtual void AdapterOn() = 0;
+
+    // Called when the device adapter is truned off.

[Reilly Grant (use Gerrit), 2016/07/15 21:55:20]

s/truned/turned/

[juncai, 2016/07/18 20:14:16]

Done.

+    virtual void AdapterOff() = 0;
+
+    // Called when refreshing options.
+    virtual void Refresh() = 0;

[Reilly Grant (use Gerrit), 2016/07/15 21:55:20]

I suggest calling these "RefreshInProgress" and "RefreshComplete" or having a
single "SetRefreshing" method that takes a boolean. Same above, you can have a
single "AdapterEnabled" method.

[juncai, 2016/07/18 20:14:16]

Done.

+
+    // Called when refreshing options is complete.
+    virtual void Idle() = 0;
+
    protected:
     virtual ~Observer() {}
   };
@@ -64,6 +76,16 @@ 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 whether the chooser controller UI needs a throbber to show its
+  // status.
+  virtual bool NeedsThrobber() const = 0;

[Reilly Grant (use Gerrit), 2016/07/15 21:55:20]

This seems redundant. If the set of options is refreshing we should show a
throbber. The USB chooser will never be in the refreshing state. Actually, it
could be during the initial enumeration. It would be nice to have a throbber
then.

[juncai, 2016/07/18 20:14:16]

Done.

+
+  // Returns whether the chooser controller UI needs a text to show its status.
+  virtual bool NeedsStatus() const = 0;

[Reilly Grant (use Gerrit), 2016/07/15 21:55:20]

Maybe just call this "GetStatus" and return an empty string if no status text is
necessary.

[juncai, 2016/07/18 20:14:16]

Done.

+
   // These three functions are called just before this object is destroyed:
 
   // Called when the user selects the |index|th element from the dialog.