Add choice fields in PdfAccessibilityTree

This CL creates choice field nodes using PdfAccessibilityChoiceFieldInfo
sent from plugin process and inserts them in the PdfAccessibilityTree.

This CL also includes test to validate the creation of choice field
nodes in PdfAccessibilityTree.

Bug: 1030242
Change-Id: Ia5654344970624b06cd6f352090625dc77007879
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2287070
Commit-Queue: Mansi Awasthi <maawas@microsoft.com>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Ankit Kumar 🌪️ <ankk@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#789335}

components/pdf/renderer/pdf_accessibility_tree.cc

@@ -377,6 +377,7 @@ class PdfAccessibilityTreeBuilder {
         highlights_(page_objects.highlights),
         text_fields_(page_objects.form_fields.text_fields),
         buttons_(page_objects.form_fields.buttons),
+        choice_fields_(page_objects.form_fields.choice_fields),
         page_bounds_(page_bounds),
         page_index_(page_index),
         page_node_(page_node),
@@ -408,6 +409,7 @@ class PdfAccessibilityTreeBuilder {
     uint32_t current_highlight_index = 0;
     uint32_t current_text_field_index = 0;
     uint32_t current_button_index = 0;
+    uint32_t current_choice_field_index = 0;
     LineHelper line_helper(text_runs_);
     bool pdf_forms_enabled =
         base::FeatureList::IsEnabled(chrome_pdf::features::kAccessiblePDFForm);
@@ -461,6 +463,13 @@ class PdfAccessibilityTreeBuilder {
         AddButtonToParaNode(buttons_[current_button_index++], para_node,
                             &text_run_index);
         continue;
+      } else if (IsObjectInTextRun(choice_fields_, current_choice_field_index,
+                                   text_run_index) &&
+                 pdf_forms_enabled) {
+        FinishStaticNode(&static_text_node, &static_text);
+        AddChoiceFieldToParaNode(choice_fields_[current_choice_field_index++],
+                                 para_node, &text_run_index);
+        continue;
       } else {
         PP_PdfPageCharacterIndex page_char_index = {
             page_index_, text_run_start_indices_[text_run_index]};
@@ -529,9 +538,12 @@ class PdfAccessibilityTreeBuilder {
             base::make_span(text_fields_).subspan(current_text_field_index);
     base::span<const ppapi::PdfAccessibilityButtonInfo> remaining_buttons =
         base::make_span(buttons_).subspan(current_button_index);
+    base::span<const ppapi::PdfAccessibilityChoiceFieldInfo>
+        remaining_choice_fields =
+            base::make_span(choice_fields_).subspan(current_text_field_index);
     AddRemainingAnnotations(remaining_links, remaining_images,
                             remaining_text_fields, remaining_buttons,
-                            para_node);
+                            remaining_choice_fields, para_node);
   }
 
  private:
@@ -752,6 +764,120 @@ class PdfAccessibilityTreeBuilder {
     return button_node;
   }
 
+  ui::AXNodeData* CreateListboxOptionNode(
+      const ppapi::PdfAccessibilityChoiceFieldOptionInfo& choice_field_option,
+      ax::mojom::Restriction restriction) {
+    ui::AXNodeData* listbox_option_node =
+        CreateNode(ax::mojom::Role::kListBoxOption, restriction,
+                   render_accessibility_, nodes_);
+
+    listbox_option_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
+                                            choice_field_option.name);
+    listbox_option_node->AddBoolAttribute(ax::mojom::BoolAttribute::kSelected,
+                                          choice_field_option.is_selected);
+    listbox_option_node->AddState(ax::mojom::State::kFocusable);
+    return listbox_option_node;
+  }
+
+  ui::AXNodeData* CreateListboxNode(
+      const ppapi::PdfAccessibilityChoiceFieldInfo& choice_field,
+      ui::AXNodeData* control_node) {
+    ax::mojom::Restriction restriction = choice_field.is_read_only
+                                             ? ax::mojom::Restriction::kReadOnly
+                                             : ax::mojom::Restriction::kNone;
+    ui::AXNodeData* listbox_node = CreateNode(
+        ax::mojom::Role::kListBox, restriction, render_accessibility_, nodes_);
+
+    if (choice_field.type != PP_PRIVATECHOICEFIELD_COMBOBOX) {
+      listbox_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
+                                       choice_field.name);
+    }
+
+    ui::AXNodeData* first_selected_option = nullptr;
+    for (const ppapi::PdfAccessibilityChoiceFieldOptionInfo& option :
+         choice_field.options) {
+      ui::AXNodeData* listbox_option_node =
+          CreateListboxOptionNode(option, restriction);
+      if (!first_selected_option && listbox_option_node->GetBoolAttribute(
+                                        ax::mojom::BoolAttribute::kSelected)) {
+        first_selected_option = listbox_option_node;
+      }
+      // TODO(bug 1030242): add |listbox_option_node| specific bounds here.
+      listbox_option_node->relative_bounds.bounds =
+          PpFloatRectToGfxRectF(choice_field.bounds);
+      listbox_node->child_ids.push_back(listbox_option_node->id);
+    }
+
+    if (control_node && first_selected_option) {
+      control_node->AddIntAttribute(
+          ax::mojom::IntAttribute::kActivedescendantId,
+          first_selected_option->id);
+    }
+
+    if (choice_field.is_multi_select)
+      listbox_node->AddState(ax::mojom::State::kMultiselectable);
+    listbox_node->AddState(ax::mojom::State::kFocusable);
+    listbox_node->relative_bounds.bounds =
+        PpFloatRectToGfxRectF(choice_field.bounds);
+    return listbox_node;
+  }
+
+  ui::AXNodeData* CreateComboboxInputNode(
+      const ppapi::PdfAccessibilityChoiceFieldInfo& choice_field,
+      ax::mojom::Restriction restriction) {
+    ax::mojom::Role input_role = choice_field.has_editable_text_box
+                                     ? ax::mojom::Role::kTextFieldWithComboBox
+                                     : ax::mojom::Role::kComboBoxMenuButton;
+    ui::AXNodeData* combobox_input_node =
+        CreateNode(input_role, restriction, render_accessibility_, nodes_);
+    combobox_input_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
+                                            choice_field.name);
+    for (const ppapi::PdfAccessibilityChoiceFieldOptionInfo& option :
+         choice_field.options) {
+      if (option.is_selected) {
+        combobox_input_node->AddStringAttribute(
+            ax::mojom::StringAttribute::kValue, option.name);
+        break;
+      }
+    }
+
+    combobox_input_node->AddState(ax::mojom::State::kFocusable);
+    combobox_input_node->relative_bounds.bounds =
+        PpFloatRectToGfxRectF(choice_field.bounds);
+    return combobox_input_node;
+  }
+
+  ui::AXNodeData* CreateComboboxNode(
+      const ppapi::PdfAccessibilityChoiceFieldInfo& choice_field) {
+    ax::mojom::Restriction restriction = choice_field.is_read_only
+                                             ? ax::mojom::Restriction::kReadOnly
+                                             : ax::mojom::Restriction::kNone;
+    ui::AXNodeData* combobox_node =
+        CreateNode(ax::mojom::Role::kComboBoxGrouping, restriction,
+                   render_accessibility_, nodes_);
+    ui::AXNodeData* input_element =
+        CreateComboboxInputNode(choice_field, restriction);
+    ui::AXNodeData* list_element =
+        CreateListboxNode(choice_field, input_element);
+    input_element->AddIntListAttribute(
+        ax::mojom::IntListAttribute::kControlsIds,
+        std::vector<int32_t>{list_element->id});
+    combobox_node->child_ids.push_back(input_element->id);
+    combobox_node->child_ids.push_back(list_element->id);
+    combobox_node->AddState(ax::mojom::State::kFocusable);
+    combobox_node->relative_bounds.bounds =
+        PpFloatRectToGfxRectF(choice_field.bounds);
+    return combobox_node;
+  }
+
+  ui::AXNodeData* CreateChoiceFieldNode(
+      const ppapi::PdfAccessibilityChoiceFieldInfo& choice_field) {
+    if (choice_field.type == PP_PRIVATECHOICEFIELD_LISTBOX)
+      return CreateListboxNode(choice_field, nullptr);
+
+    return CreateComboboxNode(choice_field);
+  }
+
   void AddTextToAXNode(uint32_t start_text_run_index,
                        uint32_t end_text_run_index,
                        ui::AXNodeData* ax_node,
@@ -919,16 +1045,28 @@ class PdfAccessibilityTreeBuilder {
     --(*text_run_index);
   }
 
+  void AddChoiceFieldToParaNode(
+      const ppapi::PdfAccessibilityChoiceFieldInfo& choice_field,
+      ui::AXNodeData* para_node,
+      size_t* text_run_index) {
+    // If the |text_run_index| is less than or equal to the choice_field's text
+    // run index, then push the choice_field ahead of the current text run.
+    ui::AXNodeData* choice_field_node = CreateChoiceFieldNode(choice_field);
+    para_node->child_ids.push_back(choice_field_node->id);
+    --(*text_run_index);
+  }
+
   void AddRemainingAnnotations(
       base::span<const ppapi::PdfAccessibilityLinkInfo> links,
       base::span<const ppapi::PdfAccessibilityImageInfo> images,
       base::span<const ppapi::PdfAccessibilityTextFieldInfo> text_fields,
       base::span<const ppapi::PdfAccessibilityButtonInfo> buttons,
+      base::span<const ppapi::PdfAccessibilityChoiceFieldInfo> choice_fields,
       ui::AXNodeData* para_node) {
     // If we don't have additional links, images or form fields to insert in the
     // tree, then return.
     if (links.empty() && images.empty() && text_fields.empty() &&
-        buttons.empty()) {
+        buttons.empty() && choice_fields.empty()) {
       return;
     }
 
@@ -966,6 +1104,14 @@ class PdfAccessibilityTreeBuilder {
         ui::AXNodeData* button_node = CreateButtonNode(button);
         para_node->child_ids.push_back(button_node->id);
       }
+
+      // Push all the choice fields not anchored to any text run to the last
+      // paragraph.
+      for (const ppapi::PdfAccessibilityChoiceFieldInfo& choice_field :
+           choice_fields) {
+        ui::AXNodeData* choice_field_node = CreateChoiceFieldNode(choice_field);
+        para_node->child_ids.push_back(choice_field_node->id);
+      }
     }
   }
 
@@ -977,6 +1123,7 @@ class PdfAccessibilityTreeBuilder {
   const std::vector<ppapi::PdfAccessibilityHighlightInfo>& highlights_;
   const std::vector<ppapi::PdfAccessibilityTextFieldInfo>& text_fields_;
   const std::vector<ppapi::PdfAccessibilityButtonInfo>& buttons_;
+  const std::vector<ppapi::PdfAccessibilityChoiceFieldInfo>& choice_fields_;
   const gfx::RectF& page_bounds_;
   uint32_t page_index_;
   ui::AXNodeData* page_node_;