ScopedPtrMap: Added Compare template parameter.

Allows clients to specify a custom comparison function (as in std::map).

Also added |mapped_type| and |key_compare| typedefs in ScopedPtrMap, for
compatibility with std::map.

BUG=478594

Review URL: https://codereview.chromium.org/1179083006

Cr-Commit-Position: refs/heads/master@{#334549}

2 files changed, 19 insertions, 2 deletions

diff --git a/base/containers/scoped_ptr_map.h b/base/containers/scoped_ptr_map.h
index 19a1153..259076f 100644
--- a/base/containers/scoped_ptr_map.h
+++ b/base/containers/scoped_ptr_map.h
@@ -5,6 +5,7 @@
 #ifndef BASE_CONTAINERS_SCOPED_PTR_MAP_H_
 #define BASE_CONTAINERS_SCOPED_PTR_MAP_H_
 
+#include <functional>
 #include <map>
 #include <utility>
 
@@ -19,11 +20,11 @@
 //
 // |ScopedPtr| must be a type scoped_ptr<T>. This is for compatibility with
 // std::map in C++11.
-template <class Key, class ScopedPtr>
+template <class Key, class ScopedPtr, class Compare = std::less<Key>>
 class ScopedPtrMap {
   MOVE_ONLY_TYPE_WITH_MOVE_CONSTRUCTOR_FOR_CPP_03(ScopedPtrMap)
 
-  using Container = std::map<Key, typename ScopedPtr::element_type*>;
+  using Container = std::map<Key, typename ScopedPtr::element_type*, Compare>;
 
  public:
   using allocator_type = typename Container::allocator_type;
@@ -32,6 +33,8 @@ class ScopedPtrMap {
   using reference = typename Container::reference;
   using const_reference = typename Container::const_reference;
   using key_type = typename Container::key_type;
+  using mapped_type = ScopedPtr;
+  using key_compare = typename Container::key_compare;
   using const_iterator = typename Container::const_iterator;
   using const_reverse_iterator = typename Container::const_reverse_iterator;
 
diff --git a/base/containers/scoped_ptr_map_unittest.cc b/base/containers/scoped_ptr_map_unittest.cc
index ef70440..1d8f179 100644
--- a/base/containers/scoped_ptr_map_unittest.cc
+++ b/base/containers/scoped_ptr_map_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "base/containers/scoped_ptr_map.h"
 
+#include <functional>
 #include <map>
 #include <utility>
 
@@ -143,6 +144,19 @@ TEST(ScopedPtrMapTest, Clear) {
   EXPECT_TRUE(scoped_map.empty());
 }
 
+TEST(ScopedPtrMapTest, Compare) {
+  // Construct a ScopedPtrMap with a custom comparison function.
+  bool destroyed = false;
+  ScopedPtrMap<int, scoped_ptr<ScopedDestroyer>, std::greater<int>> scoped_map;
+  scoped_map.insert(0, make_scoped_ptr(new ScopedDestroyer(&destroyed)));
+  scoped_map.insert(1, make_scoped_ptr(new ScopedDestroyer(&destroyed)));
+
+  auto it = scoped_map.begin();
+  EXPECT_EQ(1, it->first);
+  ++it;
+  EXPECT_EQ(0, it->first);
+}
+
 TEST(ScopedPtrMapTest, Scope) {
   bool destroyed = false;
   {