[KeyboardMap] Updating Windows impl to prioritize current layout

The API used to retrieve the list of layouts does not reflect the
order of the layouts in the control panel.  I don't see another
Win32 API which would give us that ordering so I am now grabbing
the current layout and swapping it with the first element to ensure
it is evaluated first.

BUG=832811

Change-Id: Icef22303e38be4b2680ad8636ba408fcb81239a2
Reviewed-on: https://chromium-review.googlesource.com/1130455Reviewed-by: Gary Kacmarcik <garykac@chromium.org>
Commit-Queue: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573537}

ui/events/keycodes/dom/dom_keyboard_layout_map_win.cc

@@ -6,6 +6,7 @@
 
 #include <cstdint>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "base/containers/flat_map.h"
@@ -61,6 +62,16 @@ uint32_t DomKeyboardLayoutMapWin::GetKeyboardLayoutCount() {
   }
   DCHECK_EQ(keyboard_layout_count, copy_count);
 
+  // The set of layouts returned from GetKeyboardLayoutList does not follow the
+  // the order of the layouts in the control panel so we use GetKeyboardLayout
+  // to retrieve the current layout and swap (if needed) to ensure it is always
+  // evaluated first.
+  auto iter = std::find(keyboard_layout_handles_.begin(),
+                        keyboard_layout_handles_.end(), GetKeyboardLayout(0));
+  if (iter != keyboard_layout_handles_.begin() &&
+      iter != keyboard_layout_handles_.end())
+    std::iter_swap(keyboard_layout_handles_.begin(), iter);
+
   return keyboard_layout_handles_.size();
 }