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

BUG=254066

Review URL: https://codereview.chromium.org/255903002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266403 0039d316-1c4b-4281-b951-d872f2087c98

extensions/common/url_pattern_set.cc

@@ -4,7 +4,6 @@
 
 #include "extensions/common/url_pattern_set.h"
 
-#include <algorithm>
 #include <iterator>
 
 #include "base/logging.h"
@@ -28,7 +27,6 @@ const char kInvalidURLPatternError[] = "Invalid url pattern '*'";
 void URLPatternSet::CreateDifference(const URLPatternSet& set1,
                                      const URLPatternSet& set2,
                                      URLPatternSet* out) {
-  out->ClearPatterns();
   out->patterns_ = base::STLSetDifference<std::set<URLPattern> >(
       set1.patterns_, set2.patterns_);
 }
@@ -37,22 +35,16 @@ void URLPatternSet::CreateDifference(const URLPatternSet& set1,
 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