Set FLAG_DIM_BEHIND for Bidics Prompt window

Biometric prompt used to set a background color
biometric_dialog_dim_color for dim effect, however
the dim background did not cover the statusbar and
navigationbar regions.

Use window manager approach for dim effect:
- Set FLAG_DIM_BEHIND for window layout params
- Set 0.5f dimAmount
- Transit dimAmount when animate away

Test: atest SystemUITests
Test: atest com.android.systemui.biometrics.AuthContainerViewTest
Test: enroll FPS, long press wifi hotsopt QS tile, then
      tap "Share" affordance with the QR code icon to
      bring up the biometric prompt
Bug: 237047065

Change-Id: Icbb68406357a000a61752bd03d9337acf0eb6276

packages/SystemUI/res/layout/auth_container_view.xml

@@ -23,7 +23,6 @@
         android:id="@+id/background"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:background="@color/biometric_dialog_dim_color"
         android:contentDescription="@string/biometric_dialog_empty_space_description"/>
 
     <View

packages/SystemUI/res/values/colors.xml

@@ -129,7 +129,6 @@
     <color name="smart_reply_button_stroke">@*android:color/accent_device_default</color>
 
     <!-- Biometric dialog colors -->
-    <color name="biometric_dialog_dim_color">#80000000</color>              <!-- 50% black -->
     <color name="biometric_dialog_gray">#ff757575</color>
     <color name="biometric_dialog_accent">@color/material_dynamic_primary40</color>
     <color name="biometric_dialog_error">#ffd93025</color>                  <!-- red 600 -->

packages/SystemUI/src/com/android/systemui/biometrics/AuthContainerView.java

@@ -90,6 +90,8 @@ public class AuthContainerView extends LinearLayout
     private static final int STATE_ANIMATING_OUT = 4;
     private static final int STATE_GONE = 5;
 
+    private static final float BACKGROUND_DIM_AMOUNT = 0.5f;
+
     /** Shows biometric prompt dialog animation. */
     private static final String SHOW = "show";
     /** Dismiss biometric prompt dialog animation.  */
@@ -754,6 +756,16 @@ public class AuthContainerView extends LinearLayout
                     .setDuration(animateDuration)
                     .setInterpolator(mLinearOutSlowIn)
                     .setListener(getJankListener(this, DISMISS, animateDuration))
+                    .setUpdateListener(animation -> {
+                        if (mWindowManager == null || getViewRootImpl() == null) {
+                            Log.w(TAG, "skip updateViewLayout() for dim animation.");
+                            return;
+                        }
+                        final WindowManager.LayoutParams lp = getViewRootImpl().mWindowAttributes;
+                        lp.dimAmount = (1.0f - (Float) animation.getAnimatedValue())
+                                * BACKGROUND_DIM_AMOUNT;
+                        mWindowManager.updateViewLayout(this, lp);
+                    })
                     .withLayer()
                     .start();
         });
@@ -800,7 +812,8 @@ public class AuthContainerView extends LinearLayout
     @VisibleForTesting
     static WindowManager.LayoutParams getLayoutParams(IBinder windowToken, CharSequence title) {
         final int windowFlags = WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED
-                | WindowManager.LayoutParams.FLAG_SECURE;
+                | WindowManager.LayoutParams.FLAG_SECURE
+                | WindowManager.LayoutParams.FLAG_DIM_BEHIND;
         final WindowManager.LayoutParams lp = new WindowManager.LayoutParams(
                 ViewGroup.LayoutParams.MATCH_PARENT,
                 ViewGroup.LayoutParams.MATCH_PARENT,
@@ -811,6 +824,7 @@ public class AuthContainerView extends LinearLayout
         lp.setFitInsetsTypes(lp.getFitInsetsTypes() & ~WindowInsets.Type.ime());
         lp.setTitle("BiometricPrompt");
         lp.accessibilityTitle = title;
+        lp.dimAmount = BACKGROUND_DIM_AMOUNT;
         lp.token = windowToken;
         return lp;
     }

packages/SystemUI/tests/src/com/android/systemui/biometrics/AuthContainerViewTest.kt

@@ -296,6 +296,16 @@ class AuthContainerViewTest : SysuiTestCase() {
         assertThat((layoutParams.flags and WindowManager.LayoutParams.FLAG_SECURE) != 0).isTrue()
     }
 
+    @Test
+    fun testLayoutParams_hasDimbehindWindowFlag() {
+        val layoutParams = AuthContainerView.getLayoutParams(windowToken, "")
+        val lpFlags = layoutParams.flags
+        val lpDimAmount = layoutParams.dimAmount
+
+        assertThat((lpFlags and WindowManager.LayoutParams.FLAG_DIM_BEHIND) != 0).isTrue()
+        assertThat(lpDimAmount).isGreaterThan(0f)
+    }
+
     @Test
     fun testLayoutParams_excludesImeInsets() {
         val layoutParams = AuthContainerView.getLayoutParams(windowToken, "")