WidgetPicker - Fix sliding scrim on add widget dialog.

Use the system dimming for standalone widget picker activity, as the system
is applying a default transition.


Bug: 342230362
Flag: NONE animation tweak
Test: visual

Change-Id: I278f8bf97acbfbfca652e1e6b616e2d2885ca92a

res/values-night/styles.xml

@@ -21,6 +21,9 @@
     <style name="AddItemActivityTheme" parent="@android:style/Theme.Translucent.NoTitleBar">
         <item name="widgetsTheme">@style/WidgetContainerTheme.Dark</item>
         <item name="android:windowTranslucentStatus">true</item>
+        <!-- Add the dim background here, rather than in the activity layout as the window slides
+             in from the bottom, and we don't want the scrim to slide. -->
+        <item name="android:backgroundDimEnabled">true</item>
     </style>
 
     <style name="WidgetPickerActivityTheme" parent="@android:style/Theme.Translucent.NoTitleBar">

res/values/styles.xml

@@ -427,6 +427,9 @@
         <item name="widgetsTheme">@style/WidgetContainerTheme</item>
         <item name="android:windowLightStatusBar">true</item>
         <item name="android:windowTranslucentStatus">true</item>
+        <!-- Add the dim background here, rather than in the activity layout as the window slides
+             in from the bottom, and we don't want the scrim to slide. -->
+        <item name="android:backgroundDimEnabled">true</item>
     </style>
 
     <style name="ProxyActivityStarterTheme" parent="@android:style/Theme.Translucent.NoTitleBar">

src/com/android/launcher3/widget/AddItemWidgetsBottomSheet.java

@@ -145,7 +145,10 @@ public class AddItemWidgetsBottomSheet extends AbstractSlideInView<AddItemActivi
 
     @Override
     protected int getScrimColor(Context context) {
-        return context.getResources().getColor(R.color.widgets_picker_scrim);
+        // Don't add a scrim when using the standalone picker activity. The background dimming is
+        // handled by applying dimBackground in the activity theme, so the scrim doesn't slide in
+        // with the window.
+        return -1;
     }
 
     @SuppressLint("NewApi") // Already added API check.