Add support for accessible labels for controls.

This implements TitleUIElement on Mac, and IAccessibleRelation
on Windows.

BUG=89197
TEST=Manual testing with JAWS, NVDA, and VoiceOver.

Review URL: http://codereview.chromium.org/8359012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@106787 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 279 insertions, 14 deletions

diff --git a/content/browser/accessibility/browser_accessibility.cc b/content/browser/accessibility/browser_accessibility.cc
index f9ed6a2..6a6b5f7 100644
--- a/content/browser/accessibility/browser_accessibility.cc
+++ b/content/browser/accessibility/browser_accessibility.cc
@@ -255,3 +255,15 @@ bool BrowserAccessibility::IsEditableText() const {
   return (role_ == WebAccessibility::ROLE_TEXT_FIELD ||
           role_ == WebAccessibility::ROLE_TEXTAREA);
 }
+
+string16 BrowserAccessibility::GetTextRecursive() const {
+  if (!name_.empty()) {
+    return name_;
+  }
+
+  string16 result;
+  for (size_t i = 0; i < children_.size(); ++i)
+    result += children_[i]->GetTextRecursive();
+  return result;
+}
+
diff --git a/content/browser/accessibility/browser_accessibility.h b/content/browser/accessibility/browser_accessibility.h
index 80a0250..9ae0dc9 100644
--- a/content/browser/accessibility/browser_accessibility.h
+++ b/content/browser/accessibility/browser_accessibility.h
@@ -220,6 +220,9 @@ class CONTENT_EXPORT BrowserAccessibility {
   // Returns true if this node is an editable text field of any kind.
   bool IsEditableText() const;
 
+  // Append the text from this node and its children.
+  string16 GetTextRecursive() const;
+
  protected:
   BrowserAccessibility();
 
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.mm b/content/browser/accessibility/browser_accessibility_cocoa.mm
index 162d0f8..cf3ecc3 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.mm
+++ b/content/browser/accessibility/browser_accessibility_cocoa.mm
@@ -194,6 +194,7 @@ static const AttributeToMethodNameEntry attributeToMethodNameContainer[] = {
   { NSAccessibilitySubroleAttribute, @"subrole" },
   { NSAccessibilityTabsAttribute, @"tabs" },
   { NSAccessibilityTitleAttribute, @"title" },
+  { NSAccessibilityTitleUIElementAttribute, @"titleUIElement" },
   { NSAccessibilityTopLevelUIElementAttribute, @"window" },
   { NSAccessibilityURLAttribute, @"url" },
   { NSAccessibilityValueAttribute, @"value" },
@@ -570,6 +571,18 @@ NSDictionary* attributeToMethodNameMap = nil;
   return base::SysUTF16ToNSString(browserAccessibility_->name());
 }
 
+- (id)titleUIElement {
+  int titleElementId;
+  if (browserAccessibility_->GetIntAttribute(
+          WebAccessibility::ATTR_TITLE_UI_ELEMENT, &titleElementId)) {
+    BrowserAccessibility* titleElement =
+        browserAccessibility_->manager()->GetFromRendererID(titleElementId);
+    if (titleElement)
+      return titleElement->toBrowserAccessibilityCocoa();
+  }
+  return nil;
+}
+
 - (NSString*)url {
   StringAttribute urlAttribute =
       [[self role] isEqualToString:@"AXWebArea"] ?
@@ -862,6 +875,15 @@ NSDictionary* attributeToMethodNameMap = nil;
         nil]];
   }
 
+  // Title UI Element.
+  int i;
+  if (browserAccessibility_->GetIntAttribute(
+          WebAccessibility::ATTR_TITLE_UI_ELEMENT, &i)) {
+    [ret addObjectsFromArray:[NSArray arrayWithObjects:
+         NSAccessibilityTitleUIElementAttribute,
+         nil]];
+  }
+
   return ret;
 }
 
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index 12960ea..7be2664 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -7,6 +7,7 @@
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
+#include "base/win/scoped_comptr.h"
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
 #include "content/common/view_messages.h"
 #include "net/base/escape.h"
@@ -22,6 +23,133 @@ const GUID GUID_ISimpleDOM = {
     0x0c539790, 0x12e4, 0x11cf,
     0xb6, 0x61, 0x00, 0xaa, 0x00, 0x4c, 0xd6, 0xd8};
 
+//
+// BrowserAccessibilityRelation
+//
+// A simple implementation of IAccessibleRelation, used to represent
+// a relationship between two accessible nodes in the tree.
+//
+
+class BrowserAccessibilityRelation
+    : public CComObjectRootEx<CComMultiThreadModel>,
+      public IAccessibleRelation {
+  BEGIN_COM_MAP(BrowserAccessibilityRelation)
+    COM_INTERFACE_ENTRY(IAccessibleRelation)
+  END_COM_MAP()
+
+  CONTENT_EXPORT BrowserAccessibilityRelation() {}
+  CONTENT_EXPORT virtual ~BrowserAccessibilityRelation() {}
+
+  CONTENT_EXPORT void Initialize(BrowserAccessibilityWin* owner,
+                                 const string16& type);
+  CONTENT_EXPORT void AddTarget(int target_id);
+
+  // IAccessibleRelation methods.
+  CONTENT_EXPORT STDMETHODIMP get_relationType(BSTR* relation_type);
+  CONTENT_EXPORT STDMETHODIMP get_nTargets(long* n_targets);
+  CONTENT_EXPORT STDMETHODIMP get_target(long target_index, IUnknown** target);
+  CONTENT_EXPORT STDMETHODIMP get_targets(long max_targets,
+                                          IUnknown** targets,
+                                          long* n_targets);
+
+  // IAccessibleRelation methods not implemented.
+  CONTENT_EXPORT STDMETHODIMP get_localizedRelationType(BSTR* relation_type) {
+    return E_NOTIMPL;
+  }
+
+ private:
+  string16 type_;
+  base::win::ScopedComPtr<BrowserAccessibilityWin> owner_;
+  std::vector<int> target_ids_;
+};
+
+void BrowserAccessibilityRelation::Initialize(BrowserAccessibilityWin* owner,
+                                              const string16& type) {
+  owner_ = owner;
+  type_ = type;
+}
+
+void BrowserAccessibilityRelation::AddTarget(int target_id) {
+  target_ids_.push_back(target_id);
+}
+
+STDMETHODIMP BrowserAccessibilityRelation::get_relationType(
+    BSTR* relation_type) {
+  if (!relation_type)
+    return E_INVALIDARG;
+
+  if (!owner_->instance_active())
+    return E_FAIL;
+
+  *relation_type = SysAllocString(type_.c_str());
+  DCHECK(*relation_type);
+  return S_OK;
+}
+
+STDMETHODIMP BrowserAccessibilityRelation::get_nTargets(long* n_targets) {
+  if (!n_targets)
+    return E_INVALIDARG;
+
+  if (!owner_->instance_active())
+    return E_FAIL;
+
+  *n_targets = static_cast<long>(target_ids_.size());
+  return S_OK;
+}
+
+STDMETHODIMP BrowserAccessibilityRelation::get_target(
+    long target_index, IUnknown** target) {
+  if (!target)
+    return E_INVALIDARG;
+
+  if (!owner_->instance_active())
+    return E_FAIL;
+
+  if (target_index < 0 ||
+      target_index >= static_cast<long>(target_ids_.size())) {
+    return E_INVALIDARG;
+  }
+
+  BrowserAccessibilityManager* manager = owner_->manager();
+  BrowserAccessibility* result =
+      manager->GetFromRendererID(target_ids_[target_index]);
+  if (!result->instance_active())
+    return E_FAIL;
+
+  *target = static_cast<IAccessible*>(
+      result->toBrowserAccessibilityWin()->NewReference());
+  return S_OK;
+}
+
+STDMETHODIMP BrowserAccessibilityRelation::get_targets(
+    long max_targets, IUnknown** targets, long* n_targets) {
+  if (!targets || !n_targets)
+    return E_INVALIDARG;
+
+  if (!owner_->instance_active())
+    return E_FAIL;
+
+  long count = static_cast<long>(target_ids_.size());
+  if (count > max_targets)
+    count = max_targets;
+
+  *n_targets = count;
+  if (count == 0)
+    return S_FALSE;
+
+  for (long i = 0; i < count; ++i) {
+    HRESULT result = get_target(i, &targets[i]);
+    if (result != S_OK)
+      return result;
+  }
+
+  return S_OK;
+}
+
+//
+// BrowserAccessibilityWin
+//
+
 // static
 BrowserAccessibility* BrowserAccessibility::Create() {
   CComObject<BrowserAccessibilityWin>* instance;
@@ -43,6 +171,8 @@ BrowserAccessibilityWin::BrowserAccessibilityWin()
 }
 
 BrowserAccessibilityWin::~BrowserAccessibilityWin() {
+  for (size_t i = 0; i < relations_.size(); ++i)
+    relations_[i]->Release();
 }
 
 //
@@ -286,10 +416,24 @@ STDMETHODIMP BrowserAccessibilityWin::get_accName(VARIANT var_id, BSTR* name) {
   if (!target)
     return E_INVALIDARG;
 
-  if (target->name_.empty())
+  string16 name_str = target->name_;
+
+  // If the name is empty, see if it's labeled by another element.
+  if (name_str.empty()) {
+    int title_elem_id;
+    if (target->GetIntAttribute(WebAccessibility::ATTR_TITLE_UI_ELEMENT,
+                                &title_elem_id)) {
+      BrowserAccessibility* title_elem =
+          manager_->GetFromRendererID(title_elem_id);
+      if (title_elem)
+        name_str = title_elem->GetTextRecursive();
+    }
+  }
+
+  if (name_str.empty())
     return S_FALSE;
 
-  *name = SysAllocString(target->name_.c_str());
+  *name = SysAllocString(name_str.c_str());
 
   DCHECK(*name);
   return S_OK;
@@ -485,6 +629,59 @@ STDMETHODIMP BrowserAccessibilityWin::get_indexInParent(LONG* index_in_parent) {
   return S_OK;
 }
 
+STDMETHODIMP BrowserAccessibilityWin::get_nRelations(LONG* n_relations) {
+  if (!instance_active_)
+    return E_FAIL;
+
+  if (!n_relations)
+    return E_INVALIDARG;
+
+  *n_relations = relations_.size();
+  return S_OK;
+}
+
+STDMETHODIMP BrowserAccessibilityWin::get_relation(
+    LONG relation_index,
+    IAccessibleRelation** relation) {
+  if (!instance_active_)
+    return E_FAIL;
+
+  if (relation_index < 0 ||
+      relation_index >= static_cast<long>(relations_.size())) {
+    return E_INVALIDARG;
+  }
+
+  if (!relation)
+    return E_INVALIDARG;
+
+  relations_[relation_index]->AddRef();
+  *relation = relations_[relation_index];
+  return S_OK;
+}
+
+STDMETHODIMP BrowserAccessibilityWin::get_relations(
+    LONG max_relations,
+    IAccessibleRelation** relations,
+    LONG* n_relations) {
+  if (!instance_active_)
+    return E_FAIL;
+
+  if (!relations || !n_relations)
+    return E_INVALIDARG;
+
+  long count = static_cast<long>(relations_.size());
+  *n_relations = count;
+  if (count == 0)
+    return S_FALSE;
+
+  for (long i = 0; i < count; ++i) {
+    relations_[i]->AddRef();
+    relations[i] = relations_[i];
+  }
+
+  return S_OK;
+}
+
 //
 // IAccessibleImage methods.
 //
@@ -2200,6 +2397,26 @@ void BrowserAccessibilityWin::Initialize() {
   string16 url;
   if (value_.empty() && (ia_state_ & STATE_SYSTEM_LINKED))
     GetStringAttribute(WebAccessibility::ATTR_URL, &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.
+  int title_elem_id;
+  if (GetIntAttribute(WebAccessibility::ATTR_TITLE_UI_ELEMENT,
+                      &title_elem_id)) {
+    // Add a labelled by relationship.
+    CComObject<BrowserAccessibilityRelation>* relation;
+    HRESULT hr = CComObject<BrowserAccessibilityRelation>::CreateInstance(
+        &relation);
+    DCHECK(SUCCEEDED(hr));
+    relation->AddRef();
+    relation->Initialize(this, IA2_RELATION_LABELLED_BY);
+    relation->AddTarget(title_elem_id);
+    relations_.push_back(relation);
+  }
 }
 
 void BrowserAccessibilityWin::SendNodeUpdateEvents() {
diff --git a/content/browser/accessibility/browser_accessibility_win.h b/content/browser/accessibility/browser_accessibility_win.h
index dcd53b1..d20b650 100644
--- a/content/browser/accessibility/browser_accessibility_win.h
+++ b/content/browser/accessibility/browser_accessibility_win.h
@@ -21,6 +21,7 @@
 #include "webkit/glue/webaccessibility.h"
 
 class BrowserAccessibilityManagerWin;
+class BrowserAccessibilityRelation;
 
 using webkit_glue::WebAccessibility;
 
@@ -33,7 +34,8 @@ using webkit_glue::WebAccessibility;
 // to be used by screen readers and other assistive technology (AT).
 //
 ////////////////////////////////////////////////////////////////////////////////
-class BrowserAccessibilityWin
+class __declspec(uuid("562072fe-3390-43b1-9e2c-dd4118f5ac79"))
+BrowserAccessibilityWin
     : public BrowserAccessibility,
       public CComObjectRootEx<CComMultiThreadModel>,
       public IDispatchImpl<IAccessible2, &IID_IAccessible2,
@@ -179,20 +181,17 @@ class BrowserAccessibilityWin
   // Get this object's index in its parent object.
   CONTENT_EXPORT STDMETHODIMP get_indexInParent(LONG* index_in_parent);
 
-  // IAccessible2 methods not implemented.
-  CONTENT_EXPORT STDMETHODIMP get_extendedRole(BSTR* extended_role) {
-    return E_NOTIMPL;
-  }
-  CONTENT_EXPORT STDMETHODIMP get_nRelations(LONG* n_relations) {
-    return E_NOTIMPL;
-  }
+  CONTENT_EXPORT STDMETHODIMP get_nRelations(LONG* n_relations);
+
   CONTENT_EXPORT STDMETHODIMP get_relation(LONG relation_index,
-                                           IAccessibleRelation** relation) {
-    return E_NOTIMPL;
-  }
+                                           IAccessibleRelation** relation);
+
   CONTENT_EXPORT STDMETHODIMP get_relations(LONG max_relations,
       IAccessibleRelation** relations,
-      LONG* n_relations) {
+      LONG* n_relations);
+
+  // IAccessible2 methods not implemented.
+  CONTENT_EXPORT STDMETHODIMP get_extendedRole(BSTR* extended_role) {
     return E_NOTIMPL;
   }
   CONTENT_EXPORT STDMETHODIMP scrollTo(enum IA2ScrollType scroll_type) {
@@ -713,8 +712,12 @@ class BrowserAccessibilityWin
   // is initialized again but the text doesn't change.
   string16 old_text_;
 
+  // Relationships between this node and other nodes.
+  std::vector<BrowserAccessibilityRelation*> relations_;
+
   // Give BrowserAccessibility::Create access to our constructor.
   friend class BrowserAccessibility;
+  friend class BrowserAccessibilityRelation;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityWin);
 };
diff --git a/webkit/glue/webaccessibility.cc b/webkit/glue/webaccessibility.cc
index 8edac6f..92de74f 100644
--- a/webkit/glue/webaccessibility.cc
+++ b/webkit/glue/webaccessibility.cc
@@ -615,6 +615,9 @@ std::string WebAccessibility::DebugString(bool recursive,
       case ATTR_TABLE_CELL_ROW_SPAN:
         result += " rowspan=" + value;
         break;
+    case ATTR_TITLE_UI_ELEMENT:
+        result += " title_elem=" + value;
+        break;
     }
   }
 
@@ -787,6 +790,8 @@ void WebAccessibility::Init(const WebKit::WebAccessibilityObject& src,
     string_attributes[ATTR_HELP] = src.helpText();
   if (src.keyboardShortcut().length())
     string_attributes[ATTR_SHORTCUT] = src.keyboardShortcut();
+  if (src.titleUIElement().isValid())
+    int_attributes[ATTR_TITLE_UI_ELEMENT] = src.titleUIElement().axID();
   if (!src.url().isEmpty())
     string_attributes[ATTR_URL] = src.url().spec().utf16();
 
diff --git a/webkit/glue/webaccessibility.h b/webkit/glue/webaccessibility.h
index 9bddd5e..4167dce 100644
--- a/webkit/glue/webaccessibility.h
+++ b/webkit/glue/webaccessibility.h
@@ -209,6 +209,9 @@ struct WebAccessibility {
 
     // Tree control attributes.
     ATTR_HIERARCHICAL_LEVEL,
+
+    // Relationships between this element and other elements.
+    ATTR_TITLE_UI_ELEMENT,
   };
 
   enum FloatAttribute {