Refactor Uses of std::set to std::vector in SimpleFeature

base/stl_util.h

Index: base/stl_util.h
diff --git a/base/stl_util.h b/base/stl_util.h
index 89a53b070ef515cf81d584098e7aace8ed2ba201..cdd91b646e558111bedd24f33a33907773089e43 100644
--- a/base/stl_util.h
+++ b/base/stl_util.h
@@ -90,6 +90,16 @@ void STLDeleteContainerPairSecondPointers(ForwardIterator begin,
   }
 }
 
+// Counts the number of instances of val in a container.
+template <typename Container, typename T>
+typename std::iterator_traits<
+    typename Container::const_iterator>::difference_type
+STLCount(const Container* const container, const T& val) {

[Lei Zhang, 2015/03/26 21:48:45]

Can |container| be a const ref instead?

[robliao, 2015/03/26 21:51:48]

My initial iteration started out like that, but I changed it to const * for the
tests. 

Check out
https://codereview.chromium.org/1032023002/diff/40001/extensions/common/featu...
for the old iteration.

The const * allows for the removal of all the * references.

[miu, 2015/03/26 22:24:43]

I gotta agree with thestig@ here.  "const Container& container" would be a
declaration that the container argument is not optional (i.e., cannot be null),
whereas the pointer version you have here leaves doubt.

[robliao, 2015/03/26 23:15:50]

Changed and Updated.

+  const typename Container::const_iterator begin = container->begin();
+  const typename Container::const_iterator end = container->end();
+  return std::count(begin, end, val);
+}
+
 // To treat a possibly-empty vector as an array, use these functions.
 // If you know the array will never be empty, you can use &*v.begin()
 // directly, but that is undefined behaviour if |v| is empty.
@@ -195,6 +205,14 @@ bool ContainsKey(const Collection& collection, const Key& key) {
   return collection.find(key) != collection.end();
 }
 
+// Test to see if a collection like a vector contains a particular value.
+// Returns true if the value is in the collection.
+template <typename Collection, typename Value>
+bool ContainsValue(const Collection& collection, const Value& value) {
+  return std::find(collection.begin(), collection.end(), value) !=
+      collection.end();
+}
+
 namespace base {
 
 // Returns true if the container is sorted.