Issue 7200 - Adjust UI colors

mobile/android/base/java/org/mozilla/gecko/tabs/TabStrip.java

Index: mobile/android/base/java/org/mozilla/gecko/tabs/TabStrip.java
===================================================================
--- a/mobile/android/base/java/org/mozilla/gecko/tabs/TabStrip.java
+++ b/mobile/android/base/java/org/mozilla/gecko/tabs/TabStrip.java
@@ -180,22 +180,20 @@
     @Override
     public void onLightweightThemeChanged() {
         final Drawable drawable = getTheme().getDrawable(this);
         if (drawable == null) {
             return;
         }
 
         final StateListDrawable stateList = new StateListDrawable();
-        // Using ABB color palette. See https://issues.adblockplus.org/ticket/3769
-        stateList.addState(PRIVATE_STATE_SET, getColorDrawable(R.color.abb_background_light_grey));
+        stateList.addState(PRIVATE_STATE_SET, getColorDrawable(R.color.text_and_tabs_tray_grey));
         stateList.addState(EMPTY_STATE_SET, drawable);
 
         setBackgroundDrawable(stateList);
     }
 
     @Override
     public void onLightweightThemeReset() {
-        // Using ABB color palette. See https://issues.adblockplus.org/ticket/3769
-        final int defaultBackgroundColor = ContextCompat.getColor(getContext(), R.color.abb_background_light_grey);
+        final int defaultBackgroundColor = ContextCompat.getColor(getContext(), R.color.text_and_tabs_tray_grey);
         setBackgroundColor(defaultBackgroundColor);
     }
 }