Prevent serialization after being destroyed

Bug: 5246900

Change-Id: Ic0be139b26e1b52203b8d0286c12175df6a1a46c

core/java/android/webkit/ViewStateSerializer.java

@@ -36,11 +36,15 @@ class ViewStateSerializer {
 
     static boolean serializeViewState(OutputStream stream, WebView web)
             throws IOException {
+        int baseLayer = web.getBaseLayer();
+        if (baseLayer == 0) {
+            return false;
+        }
         DataOutputStream dos = new DataOutputStream(stream);
         dos.writeInt(VERSION);
         dos.writeInt(web.getContentWidth());
         dos.writeInt(web.getContentHeight());
-        return nativeSerializeViewState(web.getBaseLayer(), dos,
+        return nativeSerializeViewState(baseLayer, dos,
                 new byte[WORKING_STREAM_STORAGE]);
     }
 

core/java/android/webkit/WebView.java

@@ -4311,6 +4311,9 @@ public class WebView extends AbsoluteLayout
     }
 
     int getBaseLayer() {
+        if (mNativeClass == 0) {
+            return 0;
+        }
         return nativeGetBaseLayer();
     }