Add API to get compatibility display id

Add an API to get the compatibility display ID from CompatibilityDisplay
in the framework.

Testing Done: Compiled, built and used this API from ActivityManager and
it works.

Bug: 36071574
Change-Id: Ie4d1eb6a6befa7dbc3413519de20e2762529079d
Signed-off-by: Karthik Ravi Shankar <karthikrs@google.com>

core/java/android/service/vr/IVrManager.aidl

@@ -50,5 +50,13 @@ interface IVrManager {
      * @param enabled true if the device should be placed in persistent VR mode.
      */
     void setPersistentVrModeEnabled(in boolean enabled);
+
+    /**
+     * Return current virtual display id.
+     *
+     * @return {@link android.view.Display.INVALID_DISPLAY} if there is no virtual display
+     * currently, else return the display id of the virtual display
+     */
+    int getCompatibilityDisplayId();
 }
 

services/core/java/com/android/server/vr/CompatibilityDisplay.java

@@ -1,6 +1,8 @@
 
 package com.android.server.vr;
 
+import static android.view.Display.INVALID_DISPLAY;
+
 import android.app.Service;
 import android.content.BroadcastReceiver;
 import android.content.Context;
@@ -86,10 +88,8 @@ class CompatibilityDisplay {
                 startVirtualDisplay();
             }
         } else {
-            // TODO: Remove conditional when launching apps 2D doesn't force VrMode to stop.
-            if (!DEBUG) {
-                stopVirtualDisplay();
-            }
+            // Stop virtual display to test exit condition
+            stopVirtualDisplay();
         }
     }
 
@@ -138,6 +138,19 @@ class CompatibilityDisplay {
         }
     }
 
+    public int getVirtualDisplayId() {
+        synchronized(vdLock) {
+            if (mVirtualDisplay != null) {
+                int virtualDisplayId = mVirtualDisplay.getDisplay().getDisplayId();
+                if (DEBUG) {
+                    Log.e(TAG, "VD id: " + virtualDisplayId);
+                }
+                return virtualDisplayId;
+            }
+        }
+        return INVALID_DISPLAY;
+    }
+
     private void startVirtualDisplay() {
         if (DEBUG) {
             Log.d(TAG, "Request to start VD, DM:" + mDisplayManager);

services/core/java/com/android/server/vr/VrManagerInternal.java

@@ -89,6 +89,15 @@ public abstract class VrManagerInternal {
      */
     public abstract void setPersistentVrModeEnabled(boolean enabled);
 
+    /**
+     * Return {@link android.view.Display.INVALID_DISPLAY} if there exists no virtual display
+     * currently or the display id of the current virtual display.
+     *
+     * @return {@link android.view.Display.INVALID_DISPLAY} if there is no virtual display
+     * currently, else return the display id of the virtual display
+     */
+    public abstract int getCompatibilityDisplayId();
+
     /**
      * Adds listener that reports state changes to persistent VR mode.
      */

services/core/java/com/android/server/vr/VrManagerService.java

@@ -15,6 +15,8 @@
  */
 package com.android.server.vr;
 
+import static android.view.Display.INVALID_DISPLAY;
+
 import android.Manifest;
 import android.app.ActivityManager;
 import android.app.AppOpsManager;
@@ -391,6 +393,11 @@ public class VrManagerService extends SystemService implements EnabledComponentC
             VrManagerService.this.setPersistentVrModeEnabled(enabled);
         }
 
+        @Override
+        public int getCompatibilityDisplayId() {
+            return VrManagerService.this.getCompatibilityDisplayId();
+        }
+
         @Override
         protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
             if (getContext().checkCallingOrSelfPermission(android.Manifest.permission.DUMP)
@@ -494,6 +501,11 @@ public class VrManagerService extends SystemService implements EnabledComponentC
             VrManagerService.this.setPersistentVrModeEnabled(enabled);
         }
 
+        @Override
+        public int getCompatibilityDisplayId() {
+            return VrManagerService.this.getCompatibilityDisplayId();
+        }
+
         @Override
         public void addPersistentVrModeStateListener(PersistentVrStateListener listener) {
             VrManagerService.this.addPersistentVrModeStateListener(listener);
@@ -1054,6 +1066,14 @@ public class VrManagerService extends SystemService implements EnabledComponentC
         }
     }
 
+    private int getCompatibilityDisplayId() {
+        if (mCompatibilityDisplay != null) {
+            return mCompatibilityDisplay.getVirtualDisplayId();
+        }
+        Slog.w(TAG, "CompatibilityDisplay is null!");
+        return INVALID_DISPLAY;
+    }
+
     private void setPersistentModeAndNotifyListenersLocked(boolean enabled) {
         if (mPersistentVrModeEnabled == enabled) {
             return;