Revert of Migrate BrowserAccessibility windows unique id handling to AXPlatformNodeWin.

ui/accessibility/platform/ax_platform_node_win.cc

Index: ui/accessibility/platform/ax_platform_node_win.cc
diff --git a/ui/accessibility/platform/ax_platform_node_win.cc b/ui/accessibility/platform/ax_platform_node_win.cc
index 4d95f7dc9c57de3d032dc0f8b4f7284bbdddd383..25c8c227dd921ef147e58f955fb22fa390cf08e4 100644
--- a/ui/accessibility/platform/ax_platform_node_win.cc
+++ b/ui/accessibility/platform/ax_platform_node_win.cc
@@ -25,7 +25,6 @@
 #include "ui/accessibility/ax_tree_data.h"
 #include "ui/accessibility/platform/ax_platform_node_delegate.h"
 #include "ui/accessibility/platform/ax_platform_node_win.h"
-#include "ui/accessibility/platform/ax_platform_unique_id.h"
 #include "ui/base/win/atl_module.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 
@@ -307,34 +306,16 @@
   return ax_platform_node.Get();
 }
 
-using UniqueIdMap = base::hash_map<int32_t, AXPlatformNode*>;
-// Map from each AXPlatformNode's unique id to its instance.
-base::LazyInstance<UniqueIdMap>::DestructorAtExit g_unique_id_map =
-    LAZY_INSTANCE_INITIALIZER;
-
-// static
-AXPlatformNode* AXPlatformNodeWin::GetFromUniqueId(int32_t unique_id) {
-  UniqueIdMap* unique_ids = g_unique_id_map.Pointer();
-  auto iter = unique_ids->find(unique_id);
-  if (iter != unique_ids->end())
-    return iter->second;
-
-  return nullptr;
-}
 //
 // AXPlatformNodeWin
 //
 
-AXPlatformNodeWin::AXPlatformNodeWin()
-    : unique_id_(ui::GetNextAXPlatformNodeUniqueId()) {
-  g_unique_id_map.Get()[unique_id_] = this;
+AXPlatformNodeWin::AXPlatformNodeWin() {
 }
 
 AXPlatformNodeWin::~AXPlatformNodeWin() {
   for (ui::AXPlatformNodeRelationWin* relation : relations_)
     relation->Release();
-  if (unique_id_)
-    g_unique_id_map.Get().erase(unique_id_);
 }
 
 void AXPlatformNodeWin::CalculateRelationships() {
@@ -553,8 +534,6 @@
 void AXPlatformNodeWin::Destroy() {
   RemoveAlertTarget();
   AXPlatformNodeBase::Destroy();
-  g_unique_id_map.Get().erase(unique_id_);
-  unique_id_ = 0;
 }
 
 //