Do not make ActivityContainer available to apps.

A security leak was discovered whereby a malicious app could get the
IActivityContainer object from one app and use it to inject events
into another app. This fix removes the availability of the
IActivityContainer and replaces its one use with a method for
returning the information the IActivityContainer was used for.

Fixes bug 19394591.

Change-Id: Ib3cec25b25130cd8e098892c057742cfd575cfdd
diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index fa10893..005b1d9 100644
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -17,7 +17,6 @@
 package android.app;
 
 import android.app.ActivityManager.StackInfo;
-import android.app.ProfilerInfo;
 import android.content.ComponentName;
 import android.content.IIntentReceiver;
 import android.content.IIntentSender;
@@ -2233,17 +2232,12 @@
             return true;
         }
 
-        case GET_ACTIVITY_CONTAINER_TRANSACTION: {
+        case GET_ACTIVITY_DISPLAY_ID_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             IBinder activityToken = data.readStrongBinder();
-            IActivityContainer activityContainer = getEnclosingActivityContainer(activityToken);
+            int displayId = getActivityDisplayId(activityToken);
             reply.writeNoException();
-            if (activityContainer != null) {
-                reply.writeInt(1);
-                reply.writeStrongBinder(activityContainer.asBinder());
-            } else {
-                reply.writeInt(0);
-            }
+            reply.writeInt(displayId);
             return true;
         }
 
@@ -5298,6 +5292,7 @@
         reply.recycle();
     }
 
+    @Override
     public IActivityContainer createStackOnDisplay(int displayId) throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
@@ -5317,26 +5312,22 @@
         return res;
     }
 
-    public IActivityContainer getEnclosingActivityContainer(IBinder activityToken)
+    @Override
+    public int getActivityDisplayId(IBinder activityToken)
             throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
         data.writeStrongBinder(activityToken);
-        mRemote.transact(GET_ACTIVITY_CONTAINER_TRANSACTION, data, reply, 0);
+        mRemote.transact(GET_ACTIVITY_DISPLAY_ID_TRANSACTION, data, reply, 0);
         reply.readException();
-        final int result = reply.readInt();
-        final IActivityContainer res;
-        if (result == 1) {
-            res = IActivityContainer.Stub.asInterface(reply.readStrongBinder());
-        } else {
-            res = null;
-        }
+        final int displayId = reply.readInt();
         data.recycle();
         reply.recycle();
-        return res;
+        return displayId;
     }
 
+    @Override
     public IBinder getHomeActivityToken() throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();