Add country combobox to change country and rebuild address inputs.

chrome/browser/ui/autofill/country_combobox_model.h

Index: chrome/browser/ui/autofill/country_combobox_model.h
diff --git a/chrome/browser/ui/autofill/country_combobox_model.h b/chrome/browser/ui/autofill/country_combobox_model.h
index 74afeaee8a927b6a367c41197684dc2f8dcff032..c545d6364368b946034185d72634b692e610e45d 100644
--- a/chrome/browser/ui/autofill/country_combobox_model.h
+++ b/chrome/browser/ui/autofill/country_combobox_model.h
@@ -5,10 +5,12 @@
 #ifndef CHROME_BROWSER_UI_AUTOFILL_COUNTRY_COMBOBOX_MODEL_H_
 #define CHROME_BROWSER_UI_AUTOFILL_COUNTRY_COMBOBOX_MODEL_H_
 
+#include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
+#include "base/observer_list.h"
 #include "base/strings/string16.h"
 #include "ui/base/models/combobox_model.h"
 
@@ -23,20 +25,41 @@ class CountryComboboxModel : public ui::ComboboxModel {
   explicit CountryComboboxModel(const PersonalDataManager& manager);
   virtual ~CountryComboboxModel();
 
-  // ui::Combobox implementation:
+  // ui::ComboboxModel implementation:
   virtual int GetItemCount() const OVERRIDE;
   virtual base::string16 GetItemAt(int index) OVERRIDE;
   virtual bool IsItemSeparatorAt(int index) OVERRIDE;
+  virtual int GetDefaultIndex() const OVERRIDE;
+  virtual void AddObserver(ui::ComboboxModelObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(ui::ComboboxModelObserver* observer) OVERRIDE;
 
   const std::vector<AutofillCountry*>& countries() const {
     return countries_.get();
   }
 
+  // Clears the default country.
+  void ResetDefault();
+
+  // Changes |country_code| to the default country.
+  void SetDefaultCountry(const std::string& country_code);
+
+  // Returns the default country code for this model.
+  std::string GetDefaultCountryCode() const;
+
  private:
+  // Changes |default_index_| to |index| after checking it's sane. Notifies
+  // observers if |default_index_| changed.
+  void SetDefaultIndex(int index);
+
   // The countries to show in the model, including NULL for entries that are
   // not countries (the separator entry).
   ScopedVector<AutofillCountry> countries_;
 
+  // The index of the default country.
+  int default_index_;
+
+  ObserverList<ui::ComboboxModelObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(CountryComboboxModel);
 };