Add ManagePasswordsDecoration and unit tests.

chrome/browser/ui/passwords/manage_passwords_icon.h

Index: chrome/browser/ui/passwords/manage_passwords_icon.h
diff --git a/chrome/browser/ui/passwords/manage_passwords_icon.h b/chrome/browser/ui/passwords/manage_passwords_icon.h
index 74f8d5ba3b93b0791c81b1d669e2d134b84a156e..165374075da3b098742a3f6df8defcd96e47333f 100644
--- a/chrome/browser/ui/passwords/manage_passwords_icon.h
+++ b/chrome/browser/ui/passwords/manage_passwords_icon.h
@@ -21,6 +21,10 @@ class ManagePasswordsIcon {
   bool active() const { return active_; }
 
  protected:
+  // The ID of the icon and text resources that are currently displayed.
+  int icon_id_;
+  int tooltip_text_id_;
+
   ManagePasswordsIcon();
   ~ManagePasswordsIcon();
 
@@ -29,6 +33,9 @@ class ManagePasswordsIcon {
   virtual void UpdateVisibleUI() = 0;
 
  private:
+  // Updates the resource IDs in response to state changes.
+  void UpdateIDs();
+
   password_manager::ui::State state_;
   bool active_;