API for an Activity to enter picture-in-picture mode.

Bug: 25580820
Change-Id: I5c1bf17dd5dd92622458a61517bc9941e4ee5277
diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index f11bf742..d724823 100644
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -2759,6 +2759,13 @@
             reply.writeInt(pipMode ? 1 : 0);
             return true;
         }
+        case ENTER_PICTURE_IN_PICTURE_MODE_TRANSACTION: {
+            data.enforceInterface(IActivityManager.descriptor);
+            final IBinder token = data.readStrongBinder();
+            enterPictureInPictureMode(token);
+            reply.writeNoException();
+            return true;
+        }
         }
 
         return super.onTransact(code, data, reply, flags);
@@ -6433,5 +6440,17 @@
         return pipMode;
     }
 
+    @Override
+    public void enterPictureInPictureMode(IBinder token) throws RemoteException {
+        Parcel data = Parcel.obtain();
+        Parcel reply = Parcel.obtain();
+        data.writeInterfaceToken(IActivityManager.descriptor);
+        data.writeStrongBinder(token);
+        mRemote.transact(ENTER_PICTURE_IN_PICTURE_MODE_TRANSACTION, data, reply, 0);
+        reply.readException();
+        data.recycle();
+        reply.recycle();
+    }
+
     private IBinder mRemote;
 }