[fenix] For https://github.com/mozilla-mobile/fenix/issues/26644 - Apply the new theme earlier to the private browsing button

This will help avoid a race between the two layers of the svg, with previously
only changing the color for just one.
By applying the new theme to the button when needing to apply the textColor
from wallpaper it will automatically use the right

app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt

@@ -39,6 +39,7 @@ import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.LinearSmoothScroller
 import androidx.recyclerview.widget.RecyclerView.SmoothScroller
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat
 import com.google.android.material.appbar.AppBarLayout
 import com.google.android.material.button.MaterialButton
 import com.google.android.material.snackbar.Snackbar
@@ -993,7 +994,22 @@ class HomeFragment : Fragment() {
         }
 
         binding.wordmarkText.imageTintList = tintColor
-        binding.privateBrowsingButton.imageTintList = tintColor
+
+        // Need to preemptively apply the new theme to the private browsing button drawable
+        // See https://github.com/mozilla-mobile/fenix/issues/26644#issuecomment-1254961616
+        (activity as? HomeActivity)?.themeManager?.let { themeManager ->
+            with(binding.privateBrowsingButton) {
+                val drawable = VectorDrawableCompat.create(
+                    resources,
+                    R.drawable.private_browsing_button,
+                    resources.newTheme().apply {
+                        applyStyle(themeManager.currentThemeResource, true)
+                    },
+                )
+                setImageDrawable(drawable)
+                imageTintList = tintColor
+            }
+        }
     }
 
     private fun observeWallpaperUpdates() {