Show topology pane detached from mirror toggle

Remove the extra blue border from the topology pane and give the toggle
below it its own rounded corners.

Flag: com.android.settings.flags.display_topology_pane_in_display_list
Test: screenshots
Test: verify display blocks are still clipped to the topology holder view
Bug: b/396116157
Change-Id: I3c0f826db24e5c599c6b51f71d099976fb04cbf0

res/layout/display_topology_preference.xml

@@ -14,13 +14,19 @@
      limitations under the License.
 -->
 
+<!-- TODO(b/396116157): I cannot find the correct src of ImageView to set to
+     match the other preference items. I tried
+     @drawable/android:selectable_item_background but this is private so will
+     not compile. It should match the other items so that theme migration will
+     switch to the correct final color. -->
 <FrameLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/display_topology_pane_holder"
     android:importantForAccessibility="no"
     android:layout_height="wrap_content"
     android:layout_width="match_parent"
-    android:paddingHorizontal="@dimen/display_topology_pane_margin"
+    android:layout_marginVertical="@dimen/display_topology_pane_vertical_margin"
+    android:layout_marginHorizontal="@dimen/display_topology_pane_margin"
     android:orientation="horizontal">
     <ImageView
         android:importantForAccessibility="no"

res/values/dimens.xml

@@ -552,6 +552,7 @@
 
     <!-- Connected displays -->
     <dimen name="display_topology_pane_margin">24dp</dimen>
+    <dimen name="display_topology_pane_vertical_margin">24dp</dimen>
     <dimen name="display_block_padding">5dp</dimen>
     <dimen name="display_block_highlight_width">2dp</dimen>
     <dimen name="display_block_corner_radius">10dp</dimen>

src/com/android/settings/connecteddevice/display/DisplayTopologyPreference.kt

@@ -16,9 +16,10 @@
 
 package com.android.settings.connecteddevice.display
 
-import android.app.WallpaperManager
 import com.android.settings.R
+import com.android.settingslib.widget.GroupSectionDividerMixin
 
+import android.app.WallpaperManager
 import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.PointF
@@ -45,7 +46,7 @@ import kotlin.math.abs
  * when there is one or more extended display attached.
  */
 class DisplayTopologyPreference(context : Context)
-        : Preference(context), ViewTreeObserver.OnGlobalLayoutListener {
+        : Preference(context), ViewTreeObserver.OnGlobalLayoutListener, GroupSectionDividerMixin {
     @VisibleForTesting lateinit var mPaneContent : FrameLayout
     @VisibleForTesting lateinit var mPaneHolder : FrameLayout
     @VisibleForTesting lateinit var mTopologyHint : TextView
@@ -82,6 +83,8 @@ class DisplayTopologyPreference(context : Context)
 
         isPersistent = false
 
+        isCopyingEnabled = false
+
         injector = Injector(context)
     }