Fix WallpaperWindowToken visible update with Shell transition

With Shell transition, when mVisibleRequested is changed, it will wait
until the transition finish to update the isVisible(). As a result, if
there is a visible change before the previous transition is finished,
it will be skipped.

For example, when we first open a fullscreen app and then immediately
enter pip:
1. TRANSIT_OPEN will call to hide wallpaper and set mVisibleRequest to
false, but not commit visible until transition animation is finished.
2. TRANSIT_PIP will call to show wallpaper, but if it is started before
the OPEN transition is finsihed, it will not update the wallpaper
mVisibleRequested, which will leave the wallpaper hidden.

Fix: 210965575
Bug: 210965692
Test: atest WMShellFlickerTests:ExpandPipOnDoubleClickTest
Change-Id: I2578aafd024a3c9a6ec96079d4dc6cb740c890d2

libs/WindowManager/Shell/tests/flicker/src/com/android/wm/shell/flicker/pip/ExpandPipOnDoubleClickTest.kt

@@ -26,9 +26,6 @@ import com.android.server.wm.flicker.FlickerTestParameterFactory
 import com.android.server.wm.flicker.LAUNCHER_COMPONENT
 import com.android.server.wm.flicker.annotation.Group3
 import com.android.server.wm.flicker.dsl.FlickerBuilder
-import com.android.server.wm.flicker.helpers.isShellTransitionsEnabled
-import org.junit.Assume.assumeFalse
-import org.junit.Before
 import org.junit.FixMethodOrder
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -65,12 +62,6 @@ class ExpandPipOnDoubleClickTest(testSpec: FlickerTestParameter) : PipTransition
             }
         }
 
-    @Before
-    fun onBefore() {
-        // This CUJ don't work in shell transitions because of b/204570898 b/204562589
-        assumeFalse(isShellTransitionsEnabled)
-    }
-
     /**
      * Checks that the pip app window remains inside the display bounds throughout the whole
      * animation

services/core/java/com/android/server/wm/WallpaperWindowToken.java

@@ -107,7 +107,7 @@ class WallpaperWindowToken extends WindowToken {
     /** Returns {@code true} if visibility is changed. */
     boolean updateWallpaperWindows(boolean visible) {
         boolean changed = false;
-        if (isVisible() != visible) {
+        if (mVisibleRequested != visible) {
             ProtoLog.d(WM_DEBUG_WALLPAPER, "Wallpaper token %s visible=%b",
                     token, visible);
             setVisibility(visible);