Enable setting primary display for 3+ displays

ui/display/manager/display_layout.cc

Index: ui/display/manager/display_layout.cc
diff --git a/ui/display/manager/display_layout.cc b/ui/display/manager/display_layout.cc
index 25660de1af10c97f7f99a28c95d5557570c6a1ab..d3a08fe6297de8bf37f1be2a1beed10bc1d4cd80 100644
--- a/ui/display/manager/display_layout.cc
+++ b/ui/display/manager/display_layout.cc
@@ -214,15 +214,19 @@ bool DisplayLayout::Validate(const DisplayIdList& list,
   if (layout.placement_list.size() == 0u)
     return true;
 
-  bool has_primary_as_parent = false;
-  int64_t id = 0;

[oshima, 2016/11/22 21:47:18]

this should have been std::numeric_limits<int64_t>::min();

+  // Placements are sorted by display_id.
+  if (!std::is_sorted(layout.placement_list.begin(),
+                      layout.placement_list.end(),
+                      [](const display::DisplayPlacement& d1,
+                         const display::DisplayPlacement& d2) {
+                        return d1.display_id < d2.display_id;
+                      })) {
+    LOG(ERROR) << "PlacementList must be sorted by display_id";
+    return false;
+  }

[oshima, 2016/11/22 21:47:18]

do you need this?

[afakhry, 2016/11/22 22:16:21]

Reverted to the old way and fixed its bug.

 
+  bool has_primary_as_parent = false;
   for (const auto& placement : layout.placement_list) {
-    // Placements are sorted by display_id.
-    if (id >= placement.display_id) {
-      LOG(ERROR) << "PlacementList must be sorted by display_id";
-      return false;
-    }
     if (placement.display_id == kInvalidDisplayId) {
       LOG(ERROR) << "display_id is not initialized";
       return false;