Remove DesktopTaskView.isDesktopModeSupported

- Use Flags.eanbleDesktopWindowingMode directly
- Also clean up unnecessary and improper flag usage

Bug: 309008406
Flag: ACONFIG com.android.window.flags.enable_desktop_windowing_mode DEVELOPMENT
Test: presubmit
Change-Id: I86ce317ce577f279d2ce819d6dc1738204c2631e

quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java

@@ -62,7 +62,7 @@ import static com.android.launcher3.util.DisplayController.CHANGE_NAVIGATION_MOD
 import static com.android.launcher3.util.Executors.UI_HELPER_EXECUTOR;
 import static com.android.quickstep.util.AnimUtils.completeRunnableListCallback;
 import static com.android.quickstep.util.SplitAnimationTimings.TABLET_HOME_TO_SPLIT;
-import static com.android.quickstep.views.DesktopTaskView.isDesktopModeSupported;
+import static com.android.window.flags.Flags.enableDesktopWindowingMode;
 import static com.android.systemui.shared.system.ActivityManagerWrapper.CLOSE_SYSTEM_WINDOWS_REASON_HOME_KEY;
 import static com.android.wm.shell.common.split.SplitScreenConstants.SNAP_TO_50_50;
 
@@ -259,7 +259,7 @@ public class QuickstepLauncher extends Launcher {
                         getDepthController(), getStatsLogManager(),
                         systemUiProxy, RecentsModel.INSTANCE.get(this),
                         () -> onStateBack());
-        if (isDesktopModeSupported()) {
+        if (enableDesktopWindowingMode()) {
             mDesktopRecentsTransitionController = new DesktopRecentsTransitionController(
                     getStateManager(), systemUiProxy, getIApplicationThread(),
                     getDepthController());
@@ -285,7 +285,7 @@ public class QuickstepLauncher extends Launcher {
         mTISBindHelper = new TISBindHelper(this, this::onTISConnected);
         mDepthController = new DepthController(this);
         mDesktopVisibilityController = new DesktopVisibilityController(this);
-        if (isDesktopModeSupported()) {
+        if (enableDesktopWindowingMode()) {
             mDesktopVisibilityController.registerSystemUiListener();
             mSplitSelectStateController.initSplitFromDesktopController(this);
         }
@@ -948,7 +948,7 @@ public class QuickstepLauncher extends Launcher {
 
     @Override
     public void setResumed() {
-        if (isDesktopModeSupported()) {
+        if (enableDesktopWindowingMode()) {
             DesktopVisibilityController controller = mDesktopVisibilityController;
             if (controller != null && controller.areFreeformTasksVisible()
                     && !controller.isRecentsGestureInProgress()) {