ui: Remove unused DialogModel::GetDialogLabel().

ui/base/models/dialog_model.h

Index: ui/base/models/dialog_model.h
diff --git a/ui/base/models/dialog_model.h b/ui/base/models/dialog_model.h
index 853eb283441d71808110cce5507daba1489adfcd..94f85e98e7aead84e9d6c0c0c1679039a30355fb 100644
--- a/ui/base/models/dialog_model.h
+++ b/ui/base/models/dialog_model.h
@@ -12,15 +12,12 @@
 namespace ui {
 
 // A model representing a dialog window. The model provides the content to show
-// to the user (i.e. label, title), and the ways the user can interact with it
+// to the user (i.e. title), and the ways the user can interact with it
 // (i.e. the buttons).
 class UI_BASE_EXPORT DialogModel {
  public:
   virtual ~DialogModel();
 
-  // Returns the text of show in the dialog.
-  virtual base::string16 GetDialogLabel() const = 0;
-
   // Returns the title of the dialog.
   virtual base::string16 GetDialogTitle() const = 0;