Use relative bounding boxes throughout Chrome accessibility

ui/accessibility/ax_node_data.cc

Index: ui/accessibility/ax_node_data.cc
diff --git a/ui/accessibility/ax_node_data.cc b/ui/accessibility/ax_node_data.cc
index 0191bc661d65df8f49a07a1cce9b35d77665f8ad..0f04517978c944131f8cce87eaa8c12cb85f763c 100644
--- a/ui/accessibility/ax_node_data.cc
+++ b/ui/accessibility/ax_node_data.cc
@@ -60,7 +60,8 @@ typename std::vector<std::pair<FirstType, SecondType>>::const_iterator
 AXNodeData::AXNodeData()
     : id(-1),
       role(AX_ROLE_UNKNOWN),
-      state(0xFFFFFFFF) {
+      state(0xFFFFFFFF),
+      offset_container_id(-1) {
 }
 
 AXNodeData::~AXNodeData() {
@@ -78,6 +79,7 @@ AXNodeData::AXNodeData(const AXNodeData& other) {
   html_attributes = other.html_attributes;
   child_ids = other.child_ids;
   location = other.location;
+  offset_container_id = other.offset_container_id;
   if (other.transform)
     transform.reset(new gfx::Transform(*other.transform));
 }
@@ -94,8 +96,11 @@ AXNodeData& AXNodeData::operator=(AXNodeData other) {
   html_attributes = other.html_attributes;
   child_ids = other.child_ids;
   location = other.location;
+  offset_container_id = other.offset_container_id;
   if (other.transform)
     transform.reset(new gfx::Transform(*other.transform));
+  else
+    transform.reset(nullptr);
   return *this;
 }
 
@@ -343,6 +348,9 @@ std::string AXNodeData::ToString() const {
                    IntToString(location.width()) + ", " +
                    IntToString(location.height()) + ")";
 
+  if (offset_container_id != -1)
+    result += " offset_container_id=" + IntToString(offset_container_id);
+
   if (transform && !transform->IsIdentity())
     result += " transform=" + transform->ToString();