Provide a mechanism to the decl. WebRequest API to match URLs without the query against a RegEx

extensions/common/matcher/regex_set_matcher.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/common/matcher/regex_set_matcher.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "extensions/common/matcher/substring_set_matcher.h"
@@ skipping 43 matching lines @@
   filtered_re2_->AllMatches(text, atoms, &re2_ids);
 
   std::set<StringPattern::ID> matched_ids;
   for (size_t i = 0; i < re2_ids.size(); ++i) {
     StringPattern::ID id = re2_id_map_[re2_ids[i]];
     matches->insert(id);
   }
   return old_number_of_matches != matches->size();
 }
 
+bool RegexSetMatcher::IsEmpty() const {
+  return regexes_.empty();
+}
+
 std::vector<RegexSetMatcher::RE2ID> RegexSetMatcher::FindSubstringMatches(
     const std::string& text) const {
   std::set<int> atoms_set;
   substring_matcher_->Match(text, &atoms_set);
   return std::vector<RE2ID>(atoms_set.begin(), atoms_set.end());
 }
 
 void RegexSetMatcher::RebuildMatcher() {
   re2_id_map_.clear();
   filtered_re2_.reset(new re2::FilteredRE2());
@@ skipping 27 matching lines @@
         new StringPattern(strings_to_match[i], i));
   }
   substring_matcher_->RegisterPatterns(substring_patterns_);
 }
 
 void RegexSetMatcher::DeleteSubstringPatterns() {
   STLDeleteElements(&substring_patterns_);
 }
 
 }  // namespace extensions