Bug 1768157 - Remove unused menulist button styles and resources. r=jwatt

The non-native theme draws the button arrow nowadays always, so these
backgrounds never really get painted.

No behavior change.

Depends on D145713

Differential Revision: https://phabricator.services.mozilla.com/D145714

layout/forms/nsComboboxControlFrame.cpp

@@ -696,13 +696,6 @@ nsresult nsComboboxControlFrame::CreateAnonymousContent(
     // Set tabindex="-1" so that the button is not tabbable
     mButtonContent->SetAttr(kNameSpaceID_None, nsGkAtoms::tabindex, u"-1"_ns,
                             false);
-
-    WritingMode wm = GetWritingMode();
-    if (wm.IsVertical()) {
-      mButtonContent->SetAttr(kNameSpaceID_None, nsGkAtoms::orientation,
-                              wm.IsVerticalRL() ? u"left"_ns : u"right"_ns,
-                              false);
-    }
     aElements.AppendElement(mButtonContent);
   }
 

layout/style/jar.mn

@@ -11,12 +11,6 @@ toolkit.jar:
    res/noframes.css                          (res/noframes.css)
    res/scrollbars.css                        (res/scrollbars.css)
    res/forms.css                             (res/forms.css)
-   res/arrow.gif                             (res/arrow.gif)
-   res/arrow-left.gif                        (res/arrow-left.gif)
-   res/arrow-right.gif                       (res/arrow-right.gif)
-   res/arrowd.gif                            (res/arrowd.gif)
-   res/arrowd-left.gif                       (res/arrowd-left.gif)
-   res/arrowd-right.gif                      (res/arrowd-right.gif)
    res/accessiblecaret-normal@1x.png         (res/accessiblecaret-normal@1x.png)
    res/accessiblecaret-normal@1.5x.png       (res/accessiblecaret-normal@1.5x.png)
    res/accessiblecaret-normal@2x.png         (res/accessiblecaret-normal@2x.png)

layout/style/res/forms.css

@@ -269,9 +269,6 @@ select > button {
   inline-size: 12px;
   white-space: nowrap;
   position: static;
-  background-image: url("arrow.gif");
-  background-repeat: no-repeat;
-  background-position: center;
   appearance: auto;
   -moz-default-appearance: -moz-menulist-arrow-button;
 
@@ -287,26 +284,6 @@ select > button {
   vertical-align: top;
 }
 
-select > button:active {
-  background-image: url("arrowd.gif") !important;
-}
-
-select > button[orientation="left"] {
-  background-image: url("arrow-left.gif") !important;
-}
-
-select > button[orientation="right"] {
-  background-image: url("arrow-right.gif") !important;
-}
-
-select > button[orientation="left"]:active {
-  background-image: url("arrowd-left.gif") !important;
-}
-
-select > button[orientation="right"]:active {
-  background-image: url("arrowd-right.gif") !important;
-}
-
 *|*::-moz-display-comboboxcontrol-frame {
   content: inherit;
   overflow: clip;