Read system decor support status from WM

There is no way to add FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS to
hardware or simulated displays, so wallpaper, IME and nav bar were
not showing up even when desktop mode developer option was enabled.

Bug: 123199549
Bug: 125007644
Bug: 124073468
Bug: 124073384
Test: Enable force desktop mode, reboot, create simulated display
Change-Id: Id6f2f3746407467f20c1f26e735b84653e34625d

3 files changed, 25 insertions, 14 deletions

diff --git a/core/java/android/view/Display.java b/core/java/android/view/Display.java
index 94a9a1c0ff30..5df7341892e2 100644
--- a/core/java/android/view/Display.java
+++ b/core/java/android/view/Display.java
@@ -21,7 +21,6 @@ import static android.Manifest.permission.CONFIGURE_DISPLAY_COLOR_MODE;
 import android.annotation.IntDef;
 import android.annotation.Nullable;
 import android.annotation.RequiresPermission;
-import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
 import android.app.KeyguardManager;
 import android.content.res.CompatibilityInfo;
@@ -231,7 +230,6 @@ public final class Display {
      * bar, navigation bar, home activity or IME.
      * </p>
      *
-     * @see #supportsSystemDecorations
      * @hide
      */
     // TODO (b/114338689): Remove the flag and use IWindowManager#setShouldShowSystemDecors
@@ -907,18 +905,6 @@ public final class Display {
     }
 
     /**
-     * Returns whether this display should support showing system decorations.
-     *
-     * @see #FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS
-     * @hide
-     */
-    @TestApi
-    // TODO (b/114338689): Remove the method and use IWindowManager#shouldShowSystemDecors
-    public boolean supportsSystemDecorations() {
-        return (mDisplayInfo.flags & FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS) != 0;
-    }
-
-    /**
      * Returns the display's HDR capabilities.
      *
      * @see #isHdr()
diff --git a/core/java/android/view/WindowManager.java b/core/java/android/view/WindowManager.java
index 6326c591aa04..a9a67ea4ec8c 100644
--- a/core/java/android/view/WindowManager.java
+++ b/core/java/android/view/WindowManager.java
@@ -481,6 +481,7 @@ public interface WindowManager extends ViewManager {
      *
      * @param displayId The id of the display.
      * @param shouldShow Indicates that the display should show system decors.
+     * @see #shouldShowSystemDecors(int)
      * @hide
      */
     @TestApi
@@ -488,6 +489,21 @@ public interface WindowManager extends ViewManager {
     }
 
     /**
+     * Checks if the display supports showing system decors.
+     * <p>
+     * System decors include status bar, navigation bar, launcher.
+     * </p>
+     *
+     * @param displayId The id of the display.
+     * @see #setShouldShowSystemDecors(int, boolean)
+     * @hide
+     */
+    @TestApi
+    default boolean shouldShowSystemDecors(int displayId) {
+        return false;
+    }
+
+    /**
      * Sets that the display should show IME.
      *
      * @param displayId Display ID.
diff --git a/core/java/android/view/WindowManagerImpl.java b/core/java/android/view/WindowManagerImpl.java
index a102f6c8a74d..2e4db5c4eef9 100644
--- a/core/java/android/view/WindowManagerImpl.java
+++ b/core/java/android/view/WindowManagerImpl.java
@@ -177,6 +177,15 @@ public final class WindowManagerImpl implements WindowManager {
     }
 
     @Override
+    public boolean shouldShowSystemDecors(int displayId) {
+        try {
+            return WindowManagerGlobal.getWindowManagerService().shouldShowSystemDecors(displayId);
+        } catch (RemoteException e) {
+        }
+        return false;
+    }
+
+    @Override
     public void setShouldShowIme(int displayId, boolean shouldShow) {
         try {
             WindowManagerGlobal.getWindowManagerService().setShouldShowIme(displayId, shouldShow);