Clean up role overriding code, add DCHECK

If the role logic needs to be overridden, do it via
DetermineAccessibilityRole() or Init(). Do not allow RoleValue() to be
overridden, as the role must no vary during the lifetime of an object.

Bug: None
Change-Id: I14bda422895924f495be13e67de1a598ccbebeb7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2598621
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#838756}

third_party/blink/renderer/modules/accessibility/ax_image_map_link.cc

@@ -61,19 +61,17 @@ AXObject* AXImageMapLink::ComputeParent() const {
   return AXObjectCache().GetOrCreate(MapElement()->GetLayoutObject());
 }
 
-ax::mojom::Role AXImageMapLink::RoleValue() const {
-  const AtomicString& aria_role =
-      GetAOMPropertyOrARIAAttribute(AOMStringProperty::kRole);
-  if (!aria_role.IsEmpty())
-    return AXObject::AriaRoleToWebCoreRole(aria_role);
-
+ax::mojom::blink::Role AXImageMapLink::DetermineAccessibilityRole() {
   // https://www.w3.org/TR/html-aam-1.0/#html-element-role-mappings
   // <area> tags without an href should be treated as static text.
   KURL url = Url();
-  if (url.IsNull() || url.IsEmpty())
-    return ax::mojom::Role::kStaticText;
+  native_role_ = url.IsNull() || url.IsEmpty()
+                     ? ax::mojom::blink::Role::kStaticText
+                     : ax::mojom::blink::Role::kLink;
 
-  return ax::mojom::Role::kLink;
+  aria_role_ = DetermineAriaRoleAttribute();
+  return aria_role_ == ax::mojom::blink::Role::kUnknown ? native_role_
+                                                        : aria_role_;
 }
 
 bool AXImageMapLink::ComputeAccessibilityIsIgnored(

third_party/blink/renderer/modules/accessibility/ax_image_map_link.h

@@ -50,7 +50,7 @@ class AXImageMapLink final : public AXNodeObject {
 
   HTMLMapElement* MapElement() const;
 
-  ax::mojom::Role RoleValue() const override;
+  ax::mojom::blink::Role DetermineAccessibilityRole() override;
   bool ComputeAccessibilityIsIgnored(IgnoredReasons* = nullptr) const override;
 
   Element* AnchorElement() const override;

third_party/blink/renderer/modules/accessibility/ax_inline_text_box.cc

@@ -51,10 +51,6 @@ AXInlineTextBox::AXInlineTextBox(
     AXObjectCacheImpl& ax_object_cache)
     : AXObject(ax_object_cache), inline_text_box_(std::move(inline_text_box)) {}
 
-ax::mojom::blink::Role AXInlineTextBox::RoleValue() const {
-  return ax::mojom::blink::Role::kInlineTextBox;
-}
-
 void AXInlineTextBox::GetRelativeBounds(AXObject** out_container,
                                         FloatRect& out_bounds_in_container,
                                         SkMatrix44& out_container_transform,
@@ -325,7 +321,9 @@ void AXInlineTextBox::GetDocumentMarkers(
   }
 }
 
-void AXInlineTextBox::Init() {}
+void AXInlineTextBox::Init() {
+  role_ = ax::mojom::blink::Role::kInlineTextBox;
+}
 
 void AXInlineTextBox::Detach() {
   inline_text_box_ = nullptr;

third_party/blink/renderer/modules/accessibility/ax_inline_text_box.h

@@ -46,7 +46,6 @@ class AXInlineTextBox final : public AXObject {
   AXInlineTextBox(scoped_refptr<AbstractInlineTextBox>, AXObjectCacheImpl&);
 
   // AXObject overrides.
-  ax::mojom::blink::Role RoleValue() const override;
   String GetName(ax::mojom::blink::NameFrom&,
                  AXObject::AXObjectVector* name_objects) const override;
   void TextCharacterOffsets(Vector<int>&) const override;

third_party/blink/renderer/modules/accessibility/ax_menu_list_option.cc

@@ -53,18 +53,6 @@ LocalFrameView* AXMenuListOption::DocumentFrameView() const {
   return element_->GetDocument().View();
 }
 
-ax::mojom::Role AXMenuListOption::RoleValue() const {
-  const AtomicString& aria_role =
-      GetAOMPropertyOrARIAAttribute(AOMStringProperty::kRole);
-  if (aria_role.IsEmpty())
-    return ax::mojom::Role::kMenuListOption;
-
-  ax::mojom::Role role = AriaRoleToWebCoreRole(aria_role);
-  if (role != ax::mojom::Role::kUnknown)
-    return role;
-  return ax::mojom::Role::kMenuListOption;
-}
-
 Element* AXMenuListOption::ActionElement() const {
   return element_;
 }

third_party/blink/renderer/modules/accessibility/ax_menu_list_option.h

@@ -48,7 +48,6 @@ class AXMenuListOption final : public AXNodeObject {
   void Detach() override;
   bool IsDetached() const override { return !element_; }
   LocalFrameView* DocumentFrameView() const override;
-  ax::mojom::Role RoleValue() const override;
   bool CanHaveChildren() const override { return false; }
   AXObject* ComputeParent() const override;
 

third_party/blink/renderer/modules/accessibility/ax_menu_list_popup.h

@@ -51,8 +51,8 @@ class AXMenuListPopup final : public AXMockObject {
  private:
   bool IsMenuListPopup() const override { return true; }
 
-  ax::mojom::Role RoleValue() const override {
-    return ax::mojom::Role::kMenuListPopup;
+  ax::mojom::blink::Role DetermineAccessibilityRole() override {
+    return ax::mojom::blink::Role::kMenuListPopup;
   }
 
   bool IsVisible() const override;

third_party/blink/renderer/modules/accessibility/ax_object.cc

@@ -592,6 +592,8 @@ AXObject::~AXObject() {
 
 void AXObject::Init() {
   role_ = DetermineAccessibilityRole();
+  DCHECK(role_ != ax::mojom::blink::Role::kUnknown)
+      << "Illegal Role::kUnknown for " << GetNode();
 }
 
 void AXObject::Detach() {
@@ -4566,8 +4568,7 @@ bool AXObject::SupportsNameFromContents(bool recursive) const {
     }
 
     case ax::mojom::blink::Role::kUnknown:
-      LOG(ERROR) << "ax::mojom::blink::Role::kUnknown for " << GetNode();
-      NOTREACHED();
+      NOTREACHED() << "Illegal Role::kUnknown for " << GetNode();
       break;
   }
 

third_party/blink/renderer/modules/accessibility/ax_object.h

@@ -413,7 +413,7 @@ class MODULES_EXPORT AXObject : public GarbageCollected<AXObject> {
   virtual bool IsVirtualObject() const;
 
   // Check object role or purpose.
-  virtual ax::mojom::blink::Role RoleValue() const;
+  ax::mojom::blink::Role RoleValue() const;
   bool IsARIATextControl() const;
   bool IsAnchor() const;
   bool IsButton() const;

third_party/blink/renderer/modules/accessibility/ax_validation_message.cc

@@ -76,8 +76,8 @@ const AtomicString& AXValidationMessage::LiveRegionRelevant() const {
   return live_region_relevant_additions;
 }
 
-ax::mojom::Role AXValidationMessage::RoleValue() const {
-  return ax::mojom::Role::kAlert;
+ax::mojom::blink::Role AXValidationMessage::DetermineAccessibilityRole() {
+  return ax::mojom::blink::Role::kAlert;
 }
 
 ListedElement* AXValidationMessage::RelatedFormControlIfVisible() const {

third_party/blink/renderer/modules/accessibility/ax_validation_message.h

@@ -42,7 +42,7 @@ class AXValidationMessage final : public AXMockObject {
                          ax::mojom::NameFrom&,
                          AXRelatedObjectVector*,
                          NameSources*) const override;
-  ax::mojom::Role RoleValue() const override;
+  ax::mojom::blink::Role DetermineAccessibilityRole() override;
 
   ListedElement* RelatedFormControlIfVisible() const;