[fenix] For https://github.com/mozilla-mobile/fenix/issues/24082 - Use Layer2 for the tab tray thumbnail item background color

app/src/main/res/layout/tab_preview.xml

@@ -9,7 +9,7 @@
         android:id="@+id/previewThumbnail"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:background="?tabTrayThumbnailItemBackground" />
+        android:background="?layer2" />
 
     <LinearLayout
         android:id="@+id/fakeToolbar"

app/src/main/res/layout/tab_tray_grid_item.xml

@@ -92,8 +92,7 @@ A FrameLayout here is an efficient way of having a views stack while allowing:
                 style="@style/Widget.MaterialComponents.CardView"
                 android:layout_width="match_parent"
                 android:layout_height="@dimen/tab_tray_grid_item_thumbnail_height"
-                android:backgroundTint="?tabTrayThumbnailItemBackground"
-                app:cardBackgroundColor="@color/photonWhite"
+                app:cardBackgroundColor="?layer2"
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintTop_toBottomOf="@+id/horizonatal_divider">
 

app/src/main/res/layout/tab_tray_item.xml

@@ -33,8 +33,7 @@
         android:layout_marginStart="16dp"
         android:layout_marginTop="8dp"
         android:layout_marginBottom="8dp"
-        android:backgroundTint="?tabTrayThumbnailItemBackground"
-        app:cardBackgroundColor="@color/photonWhite"
+        app:cardBackgroundColor="?layer2"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent">
 

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

@@ -142,7 +142,6 @@
 
     <!-- Tab tray -->
     <color name="tab_tray_item_background_normal_theme">@color/photonDarkGrey80</color>
-    <color name="tab_tray_item_thumbnail_background_normal_theme">@color/photonDarkGrey50</color>
     <color name="tab_tray_item_thumbnail_icon_normal_theme">@color/photonDarkGrey05</color>
 
     <!-- Reader View colors -->

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

@@ -6,6 +6,8 @@
     <!-- Design system color attributes -->
 
     <!-- Layers -->
+    <!-- Card background, Menu background, Dialog, Banner -->
+    <attr name="layer2" format="reference" />
     <!-- Search -->
     <attr name="layer3" format="reference" />
     <!-- Selected tab -->
@@ -75,7 +77,6 @@
     <attr name="awesomeBarIndicatorBookmarkColor" format="reference|color"/>
 
     <!-- Tab tray -->
-    <attr name="tabTrayThumbnailItemBackground" format="reference" />
     <attr name="tabTrayThumbnailIcon" format="reference" />
 
     <declare-styleable name="TrackingProtectionCategory">

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

@@ -281,7 +281,6 @@
 
     <!-- Tab tray -->
     <color name="tab_tray_item_background_normal_theme">@color/photonLightGrey10</color>
-    <color name="tab_tray_item_thumbnail_background_normal_theme">@color/photonLightGrey10</color>
     <color name="tab_tray_item_thumbnail_icon_normal_theme">@color/photonLightGrey60</color>
 
     <!-- Bookmark buttons -->

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

@@ -34,6 +34,8 @@
         <!-- Design system color attributes -->
 
         <!-- Layers -->
+        <!-- Card background, Menu background, Dialog, Banner -->
+        <item name="layer2">@color/fx_mobile_layer_color_2</item>
         <!-- Search -->
         <item name="layer3">@color/fx_mobile_layer_color_3</item>
         <!-- Selected tab -->
@@ -108,7 +110,6 @@
         <item name="mozac_widget_favicon_background_color">@color/fx_mobile_layer_color_2</item>
         <item name="mozac_widget_favicon_border_color">@color/fx_mobile_border_color_primary</item>
 
-        <item name="tabTrayThumbnailItemBackground">@color/tab_tray_item_thumbnail_background_normal_theme</item>
         <item name="tabTrayThumbnailIcon">@color/tab_tray_item_thumbnail_icon_normal_theme</item>
 
         <!-- Drawables -->
@@ -226,6 +227,8 @@
         <!-- Design system color attributes -->
 
         <!-- Layers -->
+        <!-- Card background, Menu background, Dialog, Banner -->
+        <item name="layer2">@color/fx_mobile_private_layer_color_2</item>
         <!-- Search -->
         <item name="layer3">@color/fx_mobile_private_layer_color_3</item>
         <!-- Selected tab -->
@@ -299,7 +302,6 @@
         <item name="mozac_widget_favicon_border_color">@color/photonInk50</item>
 
         <!-- Tab Tray -->
-        <item name="tabTrayThumbnailItemBackground">@color/tab_tray_item_thumbnail_background_normal_theme</item>
         <item name="tabTrayThumbnailIcon">@color/tab_tray_item_thumbnail_icon_normal_theme</item>
 
         <!-- Drawables -->