[fenix] For https://github.com/mozilla-mobile/fenix/issues/24055 - Replace ?contrastText with Icon On Color color for Primary Buttons

app/src/main/res/values/attrs.xml

@@ -23,6 +23,8 @@
     <!-- Icon -->
     <!-- Active tab -->
     <attr name="iconActive" format="reference" />
+    <!-- Icon inverted (on color) -->
+    <attr name="iconOnColor" format="reference" />
 
     <!-- Border -->
     <!-- Default, Divider, Dotted -->

app/src/main/res/values/colors.xml

@@ -211,7 +211,7 @@
     <!-- Disabled icon -->
     <color name="fx_mobile_private_icon_color_disabled" tools:ignore="UnusedResources">@color/photonLightGrey05A40</color>
     <!-- Icon inverted (on color) -->
-    <color name="fx_mobile_private_icon_color_oncolor" tools:ignore="UnusedResources">@color/photonLightGrey05</color>
+    <color name="fx_mobile_private_icon_color_oncolor">@color/photonLightGrey05</color>
     <!-- Information -->
     <color name="fx_mobile_private_icon_color_information" tools:ignore="UnusedResources">@color/photonBlue30</color>
     <!-- Icon button -->

app/src/main/res/values/styles.xml

@@ -51,6 +51,8 @@
         <!-- Icon -->
         <!-- Active tab -->
         <item name="iconActive">@color/fx_mobile_icon_color_active</item>
+        <!-- Icon inverted (on color) -->
+        <item name="iconOnColor">@color/fx_mobile_icon_color_oncolor</item>
 
         <!-- Border -->
         <!-- Default, Divider, Dotted -->
@@ -244,6 +246,8 @@
         <!-- Icon -->
         <!-- Active tab -->
         <item name="iconActive">@color/fx_mobile_private_icon_color_active</item>
+        <!-- Icon inverted (on color) -->
+        <item name="iconOnColor">@color/fx_mobile_private_icon_color_oncolor</item>
 
         <!-- Border -->
         <!-- Default, Divider, Dotted -->
@@ -360,7 +364,7 @@
 
     <style name="PositiveButton" parent="NeutralButton">
         <item name="backgroundTint">?actionPrimary</item>
-        <item name="iconTint">?contrastText</item>
+        <item name="iconTint">?iconOnColor</item>
         <item name="android:textColor">?textActionPrimary</item>
     </style>