[mojo][bindings] Move Router exception to executor thread

This change moves throwing the exception if Router was not closed to the
executor thread to make it crash instead of just logging.

Bug: 1087098
Change-Id: I65c510bdbadedc3a0589807843c57e925c0351c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2321345Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800765}

mojo/public/java/bindings/src/org/chromium/mojo/bindings/AutoCloseableRouter.java

@@ -114,11 +114,12 @@ class AutoCloseableRouter implements Router {
                 @Override
                 public void run() {
                     close();
+                    throw new IllegalStateException(
+                            "Warning: Router objects should be explicitly closed "
+                                    + "when no longer required otherwise you may leak handles.",
+                            mAllocationException);
                 }
             });
-            throw new IllegalStateException("Warning: Router objects should be explicitly closed "
-                            + "when no longer required otherwise you may leak handles.",
-                    mAllocationException);
         }
         super.finalize();
     }