Activate comboboxes (i.e. open dropdown menu) on Enter and Space.

ui/views/controls/combobox/combobox.cc

Index: ui/views/controls/combobox/combobox.cc
diff --git a/ui/views/controls/combobox/combobox.cc b/ui/views/controls/combobox/combobox.cc
index 0a3affae4424e1cc55111190ec92b260d50f448e..02db354f2f3f1169bac84d7b1d35636894a405e2 100644
--- a/ui/views/controls/combobox/combobox.cc
+++ b/ui/views/controls/combobox/combobox.cc
@@ -601,22 +601,21 @@ bool Combobox::OnKeyPressed(const ui::KeyEvent& e) {
       new_index = GetAdjacentIndex(model(), -1, selected_index_);
       break;
 
-    // Click the button only when the button style mode.
     case ui::VKEY_SPACE:
       if (style_ == STYLE_ACTION) {
         // When pressing space, the click event will be raised after the key is
         // released.
         text_button_->SetState(Button::STATE_PRESSED);
       } else {
-        return false;
+        show_menu = true;
       }
       break;
 
-    // Click the button only when the button style mode.
     case ui::VKEY_RETURN:
-      if (style_ != STYLE_ACTION)
-        return false;
-      OnPerformAction();
+      if (style_ == STYLE_ACTION)
+        OnPerformAction();
+      else
+        show_menu = true;
       break;
 
     default: