Improves computation of IAccessible2 Hypertext.

content/browser/accessibility/browser_accessibility_win.cc

 // Copyright (c) 2012 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 "content/browser/accessibility/browser_accessibility_win.h"
 
 #include <UIAutomationClient.h>
 #include <UIAutomationCoreApi.h>
 
 #include <algorithm>
@@ skipping 2393 matching lines @@
   if (!instance_active())
     return E_FAIL;
 
   if (!hyperlink ||
       index < 0 ||
       index >= static_cast<long>(hyperlinks().size())) {
     return E_INVALIDARG;
   }
 
   int32_t id = hyperlinks()[index];
-  BrowserAccessibilityWin* link = GetFromID(id);
+  BrowserAccessibilityWin* link = nullptr;
+  if (id < 0) {
+    // We are at a tree boundary.
+    link = ToBrowserAccessibilityWin(PlatformGetChild(0));
+  } else {
+    link = GetFromID(id);
+  }
   if (!link)
     return E_FAIL;
 
   *hyperlink = static_cast<IAccessibleHyperlink*>(link->NewReference());
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_hyperlinkIndex(
     long char_index,
     long* hyperlink_index) {
@@ skipping 1077 matching lines @@
       case ui::AX_SORT_DIRECTION_OTHER:
         win_attributes_->ia2_attributes.push_back(L"sort:other");
         break;
     }
   }
 
   win_attributes_->name = GetString16Attribute(ui::AX_ATTR_NAME);
   win_attributes_->description = GetString16Attribute(ui::AX_ATTR_DESCRIPTION);
 
   base::string16 value = GetValue();
-
   // On Windows, the value of a document should be its url.
   if (GetRole() == ui::AX_ROLE_ROOT_WEB_AREA ||
       GetRole() == ui::AX_ROLE_WEB_AREA) {
     value = base::UTF8ToUTF16(manager()->GetTreeData().url);
   }
-
   // If this doesn't have a value and is linked then set its value to the url
   // attribute. This allows screen readers to read an empty link's destination.
   if (value.empty() && (ia_state() & STATE_SYSTEM_LINKED))
     value = GetString16Attribute(ui::AX_ATTR_URL);
-
   win_attributes_->value = value;
 
   // Clear any old relationships between this node and other nodes.
   for (size_t i = 0; i < relations_.size(); ++i)
     relations_[i]->Release();
   relations_.clear();
 
   // Handle title UI element.
   AddRelations(ui::AX_ATTR_CONTROLS_IDS, IA2_RELATION_CONTROLLER_FOR);
   AddRelations(ui::AX_ATTR_DESCRIBEDBY_IDS, IA2_RELATION_DESCRIBED_BY);
   AddRelations(ui::AX_ATTR_FLOWTO_IDS, IA2_RELATION_FLOWS_TO);
   AddRelations(ui::AX_ATTR_LABELLEDBY_IDS, IA2_RELATION_LABELLED_BY);
 
   UpdateRequiredAttributes();
   // If this is a web area for a presentational iframe, give it a role of
   // something other than DOCUMENT so that the fact that it's a separate doc
   // is not exposed to AT.
   if (IsWebAreaForPresentationalIframe()) {
     win_attributes_->ia_role = ROLE_SYSTEM_GROUPING;
     win_attributes_->ia2_role = ROLE_SYSTEM_GROUPING;
   }
 }
 
 void BrowserAccessibilityWin::UpdateStep2ComputeHypertext() {
-  if (PlatformIsLeaf()) {
-    if (IsSimpleTextControl())
+  if (!PlatformChildCount()) {
+    if (IsSimpleTextControl()) {
       win_attributes_->hypertext = value();
-    else {
+    } else if (IsRichTextControl()) {
+      // We don't want to expose any associated label in IA2 Hypertext.
+      return;
+    } else {
       win_attributes_->hypertext = name();
     }
 
     return;
   }
 
   // Construct the hypertext for this node, which contains the concatenation
   // of all of the static text and widespace of this node's children and an
   // embedded object character for all the other children. Build up a map from
   // the character index of each embedded object character to the id of the
   // child object it points to.
   for (unsigned int i = 0; i < PlatformChildCount(); ++i) {
     const auto child = ToBrowserAccessibilityWin(PlatformGetChild(i));
     DCHECK(child);
     // Similar to Firefox, we don't expose text-only objects in IA2 hypertext.
     if (child->IsTextOnlyObject()) {
       win_attributes_->hypertext += child->name();
     } else {
       int32_t char_offset = static_cast<int32_t>(GetText().size());
       int32_t child_id = child->GetId();
+      if (i == 0 && HasIntAttribute(ui::AX_ATTR_CHILD_TREE_ID)) {
+        // Cannot store IDs from another tree into this node. Store an invalid
+        // ID to signal that we are in this situation.
+        child_id = -1;

[dmazzoni, 2016/06/06 22:24:34]

Use a unique id instead. Every BrowserAccessibility has unique_id() and you can
use the static BrowserAccessibility::GetFromUniqueID() to retrieve it. Just
switch the meaning of the hyperlink id so it's a unique ID everywhere

+      }
       int32_t index = hyperlinks().size();
       win_attributes_->hyperlink_offset_to_index[char_offset] = index;
       win_attributes_->hyperlinks.push_back(child_id);
       win_attributes_->hypertext += kEmbeddedCharacter;
     }
   }
 }
 
 void BrowserAccessibilityWin::UpdateStep3FireEvents(bool is_subtree_creation) {
   // Fire an event when an alert first appears.
@@ skipping 443 matching lines @@
 BrowserAccessibilityWin::GetHyperlinkFromHypertextOffset(int offset) const {
   std::map<int32_t, int32_t>::iterator iterator =
       hyperlink_offset_to_index().find(offset);
   if (iterator == hyperlink_offset_to_index().end())
     return nullptr;
 
   int32_t index = iterator->second;
   DCHECK_GE(index, 0);
   DCHECK_LT(index, static_cast<int32_t>(hyperlinks().size()));
   int32_t id = hyperlinks()[index];
-  BrowserAccessibilityWin* hyperlink = GetFromID(id);
+  BrowserAccessibilityWin* hyperlink = nullptr;
+  if (id < 0) {
+    hyperlink = ToBrowserAccessibilityWin(PlatformGetChild(0));
+  } else {
+    hyperlink = GetFromID(id);
+  }
+
   if (!hyperlink)
     return nullptr;
   return hyperlink;
 }
 
 int32_t BrowserAccessibilityWin::GetHyperlinkIndexFromChild(
     const BrowserAccessibilityWin& child) const {
   if (hyperlinks().empty())
     return -1;
 
@@ skipping 1040 matching lines @@
   return static_cast<BrowserAccessibilityWin*>(obj);
 }
 
 const BrowserAccessibilityWin*
 ToBrowserAccessibilityWin(const BrowserAccessibility* obj) {
   DCHECK(!obj || obj->IsNative());
   return static_cast<const BrowserAccessibilityWin*>(obj);
 }
 
 }  // namespace content