Initial support for accessibility actions on ARC.

ui/accessibility/ax_tree_id_registry.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/accessibility/ax_tree_id_registry.h"
 
 #include "base/memory/singleton.h"
+#include "ui/accessibility/ax_host_delegate.h"
 
 namespace ui {
 
 // static
 const AXTreeIDRegistry::AXTreeID AXTreeIDRegistry::kNoAXTreeID = -1;
 
 // static
 AXTreeIDRegistry* AXTreeIDRegistry::GetInstance() {
   return base::Singleton<AXTreeIDRegistry>::get();
 }
 
 AXTreeIDRegistry::AXTreeID AXTreeIDRegistry::GetOrCreateAXTreeID(
     int process_id,
     int routing_id) {
   FrameID frame_id(process_id, routing_id);
-  std::map<FrameID, AXTreeID>::iterator it;
-  it = frame_to_ax_tree_id_map_.find(frame_id);
+  auto it = frame_to_ax_tree_id_map_.find(frame_id);
   if (it != frame_to_ax_tree_id_map_.end())
     return it->second;
 
   AXTreeID new_id = ++ax_tree_id_counter_;
   frame_to_ax_tree_id_map_[frame_id] = new_id;
   ax_tree_to_frame_id_map_[new_id] = frame_id;
 
   return new_id;
 }
 
-int AXTreeIDRegistry::CreateID() {
-  return ++ax_tree_id_counter_;
-}
-
 AXTreeIDRegistry::FrameID AXTreeIDRegistry::GetFrameID(
     AXTreeIDRegistry::AXTreeID ax_tree_id) {
-  std::map<AXTreeID, FrameID>::iterator it;
-  it = ax_tree_to_frame_id_map_.find(ax_tree_id);
+  auto it = ax_tree_to_frame_id_map_.find(ax_tree_id);
   if (it != ax_tree_to_frame_id_map_.end())
     return it->second;
 
   return FrameID(-1, -1);
 }
 
+AXTreeIDRegistry::AXTreeID AXTreeIDRegistry::GetOrCreateAXTreeID(
+    AXHostDelegate* delegate) {
+  for (auto it : id_to_host_delegate_) {
+    if (it.second == delegate)
+      return it.first;
+  }
+  id_to_host_delegate_[++ax_tree_id_counter_] = delegate;
+  return ax_tree_id_counter_;
+}
+
+AXHostDelegate* AXTreeIDRegistry::GetHostDelegate(
+    AXTreeIDRegistry::AXTreeID ax_tree_id) {
+  auto it = id_to_host_delegate_.find(ax_tree_id);
+  if (it == id_to_host_delegate_.end())
+    return nullptr;
+  return it->second;
+}
+
+void AXTreeIDRegistry::SetDesktopHostDelegate(AXHostDelegate* delegate) {
+  id_to_host_delegate_[0] = delegate;

[dmazzoni, 2017/02/20 04:50:46]

Was the user supposed to already call GetOrCreateAXTreeID with that delegate?
If so then that delegate would end up in the map twice - so it sounds like not.

Maybe the docs for SetDesktopHostDelegate should be more clear to say that
you should call it *instead* of GetOrCreateAXTreeID. Alternatively maybe
GetHostDelegate could take a second argument is_desktop.

Finally, it might be good to DCHECK that it wasn't previously set, as that'd be
an error for this to be called twice

[David Tseng, 2017/02/21 19:09:05]

Got rid of desktop specifics and added a new constructor for AXHostDelegate
taking an existing or known id. See the docs for that for more info/if it's
clear.

+}
+
 void AXTreeIDRegistry::RemoveAXTreeID(AXTreeIDRegistry::AXTreeID ax_tree_id) {
-  std::map<AXTreeID, FrameID>::iterator it;
-  it = ax_tree_to_frame_id_map_.find(ax_tree_id);
-  if (it != ax_tree_to_frame_id_map_.end()) {
-    frame_to_ax_tree_id_map_.erase(it->second);
-    ax_tree_to_frame_id_map_.erase(it);
+  auto frame_it = ax_tree_to_frame_id_map_.find(ax_tree_id);
+  if (frame_it != ax_tree_to_frame_id_map_.end()) {
+    frame_to_ax_tree_id_map_.erase(frame_it->second);
+    ax_tree_to_frame_id_map_.erase(frame_it);
+    return;
   }
+
+  auto action_it = id_to_host_delegate_.find(ax_tree_id);
+  if (action_it != id_to_host_delegate_.end())
+    id_to_host_delegate_.erase(action_it);
 }
 
 AXTreeIDRegistry::AXTreeIDRegistry() : ax_tree_id_counter_(-1) {
   // Always populate default desktop tree value (0 -> 0, 0).
   GetOrCreateAXTreeID(0, 0);
 }
 
 AXTreeIDRegistry::~AXTreeIDRegistry() {}
 
 }  // namespace ui