Fix incorrect assumption in IDMap and SmallMap tests.

base/containers/small_map_unittest.cc

Index: base/containers/small_map_unittest.cc
diff --git a/base/containers/small_map_unittest.cc b/base/containers/small_map_unittest.cc
index b911bee655dd04e71598648f042811f7353ebe98..bc76e370397b40053db342fa7e84000599a6b2b4 100644
--- a/base/containers/small_map_unittest.cc
+++ b/base/containers/small_map_unittest.cc
@@ -138,30 +138,21 @@ TEST(SmallMap, CopyConstructor) {
 }
 
 template<class inner>
-static void SmallMapToMap(SmallMap<inner> const& src, inner* dest) {
+static bool SmallMapIsSubset(SmallMap<inner> const& a,
+                             SmallMap<inner> const& b) {
   typename SmallMap<inner>::const_iterator it;
-  for (it = src.begin(); it != src.end(); ++it) {
-    dest->insert(std::make_pair(it->first, it->second));
+  for (it = a.begin(); it != a.end(); ++it) {
+    typename SmallMap<inner>::const_iterator it_in_b = b.find(it->first);
+    if (it_in_b == b.end() || it_in_b->second != it->second)
+      return false;
   }
+  return true;
 }
 
 template<class inner>
 static bool SmallMapEqual(SmallMap<inner> const& a,
                           SmallMap<inner> const& b) {
-  inner ia, ib;
-  SmallMapToMap(a, &ia);
-  SmallMapToMap(b, &ib);
-
-  // On most systems we can use operator== here, but under some lesser STL
-  // implementations it doesn't seem to work. So we manually compare.
-  if (ia.size() != ib.size())
-    return false;
-  for (typename inner::iterator ia_it = ia.begin(), ib_it = ib.begin();
-       ia_it != ia.end(); ++ia_it, ++ib_it) {
-    if (*ia_it != *ib_it)
-      return false;
-  }
-  return true;
+  return SmallMapIsSubset(a, b) && SmallMapIsSubset(b, a);
 }
 
 TEST(SmallMap, AssignmentOperator) {