Make BaseIcon.Workspace so that it can be overriden.

Bug: 188094809
Test: manual
Change-Id: Id31502e66d96806054e1cdd6549b226b2a22173e
diff --git a/res/values/styles.xml b/res/values/styles.xml
index df617ea..e139a56 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -240,7 +240,7 @@
 
 
     <!-- Icon displayed on the workspace -->
-    <style name="BaseIcon.Workspace" >
+    <style name="BaseIcon.Workspace.Shadows" parent="BaseIcon">
         <item name="android:shadowRadius">2.0</item>
         <item name="android:shadowColor">?attr/workspaceShadowColor</item>
         <item name="ambientShadowColor">?attr/workspaceAmbientShadowColor</item>
@@ -251,6 +251,10 @@
         <item name="keyShadowOffsetY">.5dp</item>
     </style>
 
+    <!-- Intentionally empty so we can override -->
+    <style name="BaseIcon.Workspace" parent="BaseIcon.Workspace.Shadows">
+    </style>
+
     <!-- Theme for the popup container -->
     <style name="PopupItem">
         <item name="android:colorControlHighlight">?attr/popupColorTertiary</item>