Add a Virtual 2D Display creator.

Listens for changes to VrMode to create/destroy a Virtual Display for 2D
apps.

Test: Logs creation/destruction of vr display while toggling vr mode.
Bug: 34280358
Change-Id: Idb52c4caa9aa0b6863cc6d2eaa55922ab81bf04a

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

@@ -0,0 +1,119 @@
+
+package com.android.server.vr;
+
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.hardware.display.DisplayManager;
+import android.hardware.display.VirtualDisplay;
+import android.os.Build;
+import android.os.Handler;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.os.ServiceManager;
+import android.service.vr.IVrStateCallbacks;
+import android.service.vr.IVrManager;
+import android.util.Log;
+
+import com.android.server.vr.VrManagerService;
+
+/**
+ * Creates a 2D Virtual Display while VR Mode is enabled. This display will be used to run and
+ * render 2D app within a VR experience. For example, bringing up the 2D calculator app in VR.
+ */
+class CompatibilityDisplay {
+    private final static String TAG = "CompatDisplay";
+    private final static boolean DEBUG = false;
+
+    // TODO: Go over these values and figure out what is best
+    private final static int HEIGHT = 960;
+    private final static int WIDTH = 720;
+    private final static int DPI = 320;
+
+    private final DisplayManager mDisplayManager;
+    private final IVrManager mVrManager;
+
+    // TODO: Lock initially created when VrStateCallback was connected through Binder. This may not
+    // be necessary with the direct access to VrManager.
+    private final Object vdLock = new Object();
+
+    private final IVrStateCallbacks mVrStateCallbacks = new IVrStateCallbacks.Stub() {
+        @Override
+        public void onVrStateChanged(boolean enabled) {
+            if (enabled != mIsVrModeEnabled) {
+                mIsVrModeEnabled = enabled;
+                if (enabled) {
+                    // TODO: Consider not creating the display until ActivityManager needs one on
+                    // which to display a 2D application.
+                    startVirtualDisplay();
+                } else {
+                    stopVirtualDisplay();
+                }
+            }
+        }
+    };
+
+    private VirtualDisplay mVirtualDisplay;
+    private boolean mIsVrModeEnabled;
+
+    public CompatibilityDisplay(DisplayManager displayManager, IVrManager vrManager) {
+        mDisplayManager = displayManager;
+        mVrManager = vrManager;
+    }
+
+    /**
+     * Initializes the compabilitiy display by listening to VR mode changes.
+     */
+    public void init() {
+        startVrModeListener();
+    }
+
+    private void startVrModeListener() {
+        if (mVrManager != null) {
+            try {
+                mVrManager.registerListener(mVrStateCallbacks);
+            } catch (RemoteException e) {
+                Log.e(TAG, "Could not register VR State listener.", e);
+            }
+        }
+    }
+
+    private void startVirtualDisplay() {
+        if (DEBUG) {
+            Log.d(TAG, "Starting VD, DM:" + mDisplayManager);
+        }
+
+        if (mDisplayManager == null) {
+            Log.w(TAG, "Cannot create virtual display because mDisplayManager == null");
+            return;
+        }
+
+        synchronized (vdLock) {
+            if (mVirtualDisplay != null) {
+                Log.e(TAG, "Starting the virtual display when one already exists", new Exception());
+                return;
+            }
+
+            mVirtualDisplay = mDisplayManager.createVirtualDisplay("VR 2D Display", WIDTH, HEIGHT,
+                    DPI,
+                    null /* Surface */, 0 /* flags */);
+        }
+
+        if (DEBUG) {
+            Log.d(TAG, "VD created: " + mVirtualDisplay);
+        }
+    }
+
+    private void stopVirtualDisplay() {
+        if (DEBUG) {
+            Log.i(TAG, "Santos, stopping VD");
+        }
+
+        synchronized (vdLock) {
+            if (mVirtualDisplay != null) {
+                mVirtualDisplay.release();
+                mVirtualDisplay = null;
+            }
+        }
+    }
+}

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

@@ -31,6 +31,7 @@ import android.content.pm.FeatureInfo;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
+import android.hardware.display.DisplayManager;
 import android.os.Binder;
 import android.os.Handler;
 import android.os.IBinder;
@@ -51,6 +52,7 @@ import android.util.ArrayMap;
 import android.util.ArraySet;
 import android.util.Slog;
 import android.util.SparseArray;
+
 import com.android.internal.R;
 import com.android.server.LocalServices;
 import com.android.server.SystemConfig;
@@ -136,6 +138,7 @@ public class VrManagerService extends SystemService implements EnabledComponentC
     private final NotificationAccessManager mNotifAccessManager = new NotificationAccessManager();
     /** Tracks the state of the screen and keyguard UI.*/
     private int mSystemSleepFlags = FLAG_NONE;
+    private CompatibilityDisplay mCompatibilityDisplay;
 
     private static final int MSG_VR_STATE_CHANGE = 0;
     private static final int MSG_PENDING_VR_STATE_CHANGE = 1;
@@ -493,6 +496,11 @@ public class VrManagerService extends SystemService implements EnabledComponentC
 
                 mComponentObserver.rebuildAll();
             }
+
+            DisplayManager dm =
+                    (DisplayManager) getContext().getSystemService(Context.DISPLAY_SERVICE);
+            mCompatibilityDisplay = new CompatibilityDisplay(dm, mVrManager);
+            mCompatibilityDisplay.init();
         } else if (phase == SystemService.PHASE_THIRD_PARTY_APPS_CAN_START) {
             synchronized (mLock) {
                 mVrModeAllowed = true;