message: Add test for FormattedText() with token inclusion predicate.
  (Addressing review comment)
diff: @@ -283,6 +283,25 @@ TEST_F(UnwrappedLineTest, FormattedTextNonEmptyWithIndent) {
  EXPECT_EQ(expected, stream.str());
  }
  +TEST_F(UnwrappedLineTest, FormattedTextSelectiveIncludeToken) {
  + const std::vector<TokenInfo> tokens = {
  + {0, "test_token1"}, {1, "test_token2"}, {2, "test_token3"}};
  + CreateTokenInfos(tokens);
  + UnwrappedLine uwline(4, pre_format_tokens_.begin());
  + AddFormatTokens(&uwline);
  + for (auto& t : pre_format_tokens_) {
  + t.before.spaces_required = 2;
  + }
  + FormattedExcerpt output(uwline);
  + std::ostringstream stream;
  + // Choose to not include test_token2 in output.
  + output.FormattedText(stream, false, [](const TokenInfo& t) {
  + return t.text() != "test_token2";
  + });
  + const char expected[] = R"(test_token1 test_token3)";
  + EXPECT_EQ(expected, stream.str());
  +}
  +
  // Make sure that formatting methods all handle the empty tokens case.
  TEST_F(UnwrappedLineTest, FormattedTextPreserveSpacesNoTokens) {
  const std::vector<TokenInfo> tokens;
  