Add stream operators for URLPattern and URLPatternSet and unit test for URLPatternSet

extensions/common/url_pattern.h

Index: extensions/common/url_pattern.h
diff --git a/extensions/common/url_pattern.h b/extensions/common/url_pattern.h
index 70109dbf03027864f7b99f1e62aa435ab2c8d499..8ac1e3bbe36d0798a5bddaa1bc5e60928fd705ab 100644
--- a/extensions/common/url_pattern.h
+++ b/extensions/common/url_pattern.h
@@ -5,6 +5,7 @@
 #define EXTENSIONS_COMMON_URL_PATTERN_H_
 
 #include <functional>
+#include <iosfwd>
 #include <string>
 #include <vector>
 
@@ -238,6 +239,8 @@ class URLPattern {
   mutable std::string spec_;
 };
 
+std::ostream& operator<<(std::ostream& out, const URLPattern& url_pattern);
+
 typedef std::vector<URLPattern> URLPatternList;
 
 #endif  // EXTENSIONS_COMMON_URL_PATTERN_H_