Fix .onion link linkification.

Fixes #11458.

app/src/test/java/org/thoughtcrime/securesms/util/LinkUtilTest_isLegal.java

@@ -0,0 +1,52 @@
+package org.thoughtcrime.securesms.util;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static junit.framework.TestCase.assertEquals;
+
+@RunWith(Parameterized.class)
+public class LinkUtilTest_isLegal {
+
+  private final String  input;
+  private final boolean output;
+
+  @Parameterized.Parameters
+  public static Collection<Object[]> data() {
+    return Arrays.asList(new Object[][]{
+        { "google.com",                            true  },
+        { "foo.google.com",                        true  },
+        { "https://foo.google.com",                true  },
+        { "https://foo.google.com/some/path.html", true  },
+        { "кц.рф",                                 true  },
+        { "https://кц.рф/some/path",               true  },
+        { "https://abcdefg.onion",                 true  },
+        { "https://abcdefg.i2p",                   true  },
+        { "http://кц.com",                         false },
+        { "кц.com",                                false },
+        { "http://asĸ.com",                        false },
+        { "http://foo.кц.рф",                      false },
+        { "кц.рф\u202C",                           false },
+        { "кц.рф\u202D",                           false },
+        { "кц.рф\u202E",                           false },
+        { "кц.рф\u2500",                           false },
+        { "кц.рф\u25AA",                           false },
+        { "кц.рф\u25FF",                           false },
+        { "",                                      false }
+    });
+  }
+
+  public LinkUtilTest_isLegal(String input, boolean output) {
+    this.input  = input;
+    this.output = output;
+  }
+
+  @Test
+  public void isLegal() {
+    assertEquals(output, LinkUtil.isLegalUrl(input));
+  }
+}