Improvements to uses of base::SmallMap

ui/ozone/platform/drm/common/drm_util.cc

Index: ui/ozone/platform/drm/common/drm_util.cc
diff --git a/ui/ozone/platform/drm/common/drm_util.cc b/ui/ozone/platform/drm/common/drm_util.cc
index 59944118ae6d2b7ae45c4049fda153ca3a770bea..ad8e25ba8fc042348e2f7a33dd923a8324740d78 100644
--- a/ui/ozone/platform/drm/common/drm_util.cc
+++ b/ui/ozone/platform/drm/common/drm_util.cc
@@ -236,7 +236,7 @@ GetAvailableDisplayControllerInfos(int fd) {
       available_connectors.push_back(std::move(connector));
   }
 
-  base::SmallMap<std::map<ScopedDrmConnectorPtr::element_type*, int>>
+  base::small_map<std::map<ScopedDrmConnectorPtr::element_type*, int>>

[danakj, 2017/04/18 21:35:50]

almost certainly there are few enough monitors that flat_map makes sense. Also
this could build a vector to init the flat_map, as it's walking thru a set of
unique keys.

[brettw, 2017/04/19 16:29:48]

Hopefully someday I can have so many monitors this code becomes slow.

       connector_crtcs;
   for (auto& c : available_connectors) {
     uint32_t possible_crtcs = 0;