Use base::STLSet* in place of std::set_* for simplicity and consistency.

extensions/common/url_pattern_set.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/url_pattern_set.h"
 
-#include <algorithm>
 #include <iterator>
 
 #include "base/logging.h"
 #include "base/memory/linked_ptr.h"
 #include "base/stl_util.h"
 #include "base/values.h"
 #include "content/public/common/url_constants.h"
 #include "extensions/common/error_utils.h"
 #include "extensions/common/url_pattern.h"
 #include "url/gurl.h"
 
 namespace extensions {
 
 namespace {
 
 const char kInvalidURLPatternError[] = "Invalid url pattern '*'";
 
 }  // namespace
 
 // static
 void URLPatternSet::CreateDifference(const URLPatternSet& set1,
                                      const URLPatternSet& set2,
                                      URLPatternSet* out) {
-  out->ClearPatterns();
   out->patterns_ = base::STLSetDifference<std::set<URLPattern> >(
       set1.patterns_, set2.patterns_);
 }
 
 // static
 void URLPatternSet::CreateIntersection(const URLPatternSet& set1,
                                        const URLPatternSet& set2,
                                        URLPatternSet* out) {
-  out->ClearPatterns();
-  std::set_intersection(set1.patterns_.begin(), set1.patterns_.end(),
-                        set2.patterns_.begin(), set2.patterns_.end(),
-                        std::inserter<std::set<URLPattern> >(
-                            out->patterns_, out->patterns_.begin()));
+  out->patterns_ = base::STLSetIntersection<std::set<URLPattern> >(
+      set1.patterns_, set2.patterns_);
 }
 
 // static
 void URLPatternSet::CreateUnion(const URLPatternSet& set1,
                                 const URLPatternSet& set2,
                                 URLPatternSet* out) {
-  out->ClearPatterns();
-  std::set_union(set1.patterns_.begin(), set1.patterns_.end(),
-                 set2.patterns_.begin(), set2.patterns_.end(),
-                 std::inserter<std::set<URLPattern> >(
-                     out->patterns_, out->patterns_.begin()));
+  out->patterns_ = base::STLSetUnion<std::set<URLPattern> >(
+      set1.patterns_, set2.patterns_);
 }
 
 // static
 void URLPatternSet::CreateUnion(const std::vector<URLPatternSet>& sets,
                                 URLPatternSet* out) {
   out->ClearPatterns();
   if (sets.empty())
     return;
 
   // N-way union algorithm is basic O(nlog(n)) merge algorithm.
@@ skipping 157 matching lines @@
   for (size_t i = 0; i < value.GetSize(); ++i) {
     std::string item;
     if (!value.GetString(i, &item))
       return false;
     patterns.push_back(item);
   }
   return Populate(patterns, valid_schemes, allow_file_access, error);
 }
 
 }  // namespace extensions