Add sparse accessibility attribute interface to Blink

content/renderer/accessibility/blink_ax_tree_source.cc

Index: content/renderer/accessibility/blink_ax_tree_source.cc
diff --git a/content/renderer/accessibility/blink_ax_tree_source.cc b/content/renderer/accessibility/blink_ax_tree_source.cc
index 0b86f3b64e71d1cc3c63870143f2595d1b05fe17..41e2a8ff7da42f6baddcbb252ddb4d62665ac652 100644
--- a/content/renderer/accessibility/blink_ax_tree_source.cc
+++ b/content/renderer/accessibility/blink_ax_tree_source.cc
@@ -55,6 +55,84 @@ namespace content {
 
 namespace {
 
+void AddIntListAttributeFromWebObjects(ui::AXIntListAttribute attr,
+                                       WebVector<WebAXObject> objects,
+                                       AXContentNodeData* dst) {
+  std::vector<int32_t> ids;
+  for (size_t i = 0; i < objects.size(); i++)
+    ids.push_back(objects[i].axID());
+  if (!ids.empty())
+    dst->AddIntListAttribute(attr, ids);
+}
+
+class SparseAttributeMap : public blink::WebAXSparseAttributeMap {

[aboxhall, 2017/01/10 05:59:59]

The name "SparseAttributeMap" is confusing me a bit, since none of these (other
than the test implementation) seem to be actual data stores but instead
selectively copy data through to some other place. In particular, they are write
only, where "Map" implies that you might be able to get the data out again.

[dmazzoni, 2017/01/12 03:36:24]

Done.

+ public:
+  SparseAttributeMap(AXContentNodeData* dst) : dst_(dst) {}
+  ~SparseAttributeMap() override {}
+
+ private:
+  AXContentNodeData* dst_;
+
+  void addBoolAttribute(blink::WebAXBoolAttribute attribute,
+                        bool value) override {
+    switch (attribute) {
+      case blink::WebAXBoolAttribute::AriaModal:
+        // TODO(dmazzoni): implement aria-modal. http://crbug.com/644766
+        break;
+      default:
+        NOTREACHED();
+    }
+  }
+
+  void addStringAttribute(blink::WebAXStringAttribute attribute,
+                          const blink::WebString& value) override {
+    switch (attribute) {
+      case blink::WebAXStringAttribute::AriaKeyShortcuts:
+        // TODO(dmazzoni): implement aria-keyshortcuts. http://crbug.com/644766
+        break;
+      case blink::WebAXStringAttribute::AriaRoleDescription:
+        // TODO(dmazzoni): implement aria-roledescription.
+        // http://crbug.com/644766
+        break;
+      default:
+        NOTREACHED();
+    }
+  }
+
+  void addObjectAttribute(blink::WebAXObjectAttribute attribute,
+                          const blink::WebAXObject& value) override {
+    switch (attribute) {
+      case blink::WebAXObjectAttribute::AriaActiveDescendant:
+        dst_->AddIntAttribute(ui::AX_ATTR_ACTIVEDESCENDANT_ID, value.axID());
+        break;
+      case blink::WebAXObjectAttribute::AriaErrorMessage:
+        // TODO

[aboxhall, 2017/01/10 05:59:59]

Any chance we could add these values in the follow-up change instead? There's so
much going on in this change already.

[dmazzoni, 2017/01/12 03:36:24]

Sure. I'll pull the new attributes into a middle change in-between this one and
the
one that was going to follow.

+        break;
+      default:
+        NOTREACHED();
+    }
+  }
+
+  void addObjectVectorAttribute(
+      blink::WebAXObjectVectorAttribute attribute,
+      const blink::WebVector<WebAXObject>& value) override {
+    switch (attribute) {
+      case blink::WebAXObjectVectorAttribute::AriaControls:
+        AddIntListAttributeFromWebObjects(ui::AX_ATTR_CONTROLS_IDS, value,
+                                          dst_);
+        break;
+      case blink::WebAXObjectVectorAttribute::AriaDetails:
+        // TODO
+        break;
+      case blink::WebAXObjectVectorAttribute::AriaFlowTo:
+        AddIntListAttributeFromWebObjects(ui::AX_ATTR_FLOWTO_IDS, value, dst_);
+        break;
+      default:
+        NOTREACHED();
+    }
+  }
+};
+
 WebAXObject ParentObjectUnignored(WebAXObject child) {
   WebAXObject parent = child.parentObject();
   while (!parent.isDetached() && parent.accessibilityIsIgnored())
@@ -109,16 +187,6 @@ std::string GetEquivalentAriaRoleString(const ui::AXRole role) {
   return std::string();
 }
 
-void AddIntListAttributeFromWebObjects(ui::AXIntListAttribute attr,
-                                       WebVector<WebAXObject> objects,
-                                       AXContentNodeData* dst) {
-  std::vector<int32_t> ids;
-  for(size_t i = 0; i < objects.size(); i++)
-    ids.push_back(objects[i].axID());
-  if (ids.size() > 0)
-    dst->AddIntListAttribute(attr, ids);
-}
-
 }  // namespace
 
 ScopedFreezeBlinkAXTreeSource::ScopedFreezeBlinkAXTreeSource(
@@ -324,6 +392,9 @@ void BlinkAXTreeSource::SerializeNode(blink::WebAXObject src,
   if (!offset_container.isDetached())
     dst->offset_container_id = offset_container.axID();
 
+  SparseAttributeMap sparse_map(dst);
+  src.getSparseAXAttributes(sparse_map);
+
   blink::WebAXNameFrom nameFrom;
   blink::WebVector<blink::WebAXObject> nameObjects;
   blink::WebString web_name = src.name(nameFrom, nameObjects);
@@ -755,14 +826,6 @@ void BlinkAXTreeSource::SerializeNode(blink::WebAXObject src,
     }
   }
 
-  WebVector<WebAXObject> controls;
-  if (src.ariaControls(controls))
-    AddIntListAttributeFromWebObjects(ui::AX_ATTR_CONTROLS_IDS, controls, dst);
-
-  WebVector<WebAXObject> flowTo;
-  if (src.ariaFlowTo(flowTo))
-    AddIntListAttributeFromWebObjects(ui::AX_ATTR_FLOWTO_IDS, flowTo, dst);
-
   if (src.isScrollableContainer()) {
     const gfx::Point& scrollOffset = src.getScrollOffset();
     dst->AddIntAttribute(ui::AX_ATTR_SCROLL_X, scrollOffset.x());