Cleanup remaining post-migration settings TODOs

The most important simplifications that were tracked by this bug have
been completed (getting rid of KitKat customizations and switching to the
material defaults). These lingering small TODOs can be removed.

AndroidPaymentAppPreference.java: There's pros and cons to using a
custom layout vs making layout changes at runtime. I generally prefer
custom layouts in XML, but it's probably not worth the effort and testing
to go back and change this one after the fact.

storage_preferences_view.xml: The default support library empty state
has smaller text, and can't be customized, so this should stay as is (UI
is by design).

Bug: 971791
Change-Id: Ie45ea27a39f8f4c66112152913864925f3bd5167
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2630067
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Auto-Submit: Natalie Chouinard <chouinard@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843733}

chrome/android/java/src/org/chromium/chrome/browser/autofill/settings/AndroidPaymentAppPreference.java

@@ -23,7 +23,6 @@ public class AndroidPaymentAppPreference extends Preference {
     public void onBindViewHolder(PreferenceViewHolder holder) {
         super.onBindViewHolder(holder);
 
-        // TODO(crbug.com/971791): Simplify this or replace it with a custom preference layout.
         int iconSize =
                 getContext().getResources().getDimensionPixelSize(R.dimen.payments_favicon_size);
         View iconView = holder.findViewById(android.R.id.icon);

components/browser_ui/site_settings/android/java/res/layout/storage_preferences_view.xml

@@ -5,11 +5,6 @@
 
 <merge xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto">
-
-    <!-- TODO(crbug.com/971791): Copied over this TextView for empty state because there are minor
-         UI differences between it and the built-in android.R.id.empty view in support library
-         preferences, but we should later investigate whether we can remove this and take advantage
-         of the default implementation instead. -->
     <TextView
         android:id="@+id/empty_storage"
         android:layout_width="match_parent"