Add interface to get relative bounding box rect of AX objects.

third_party/WebKit/Source/web/WebAXObject.cpp

Index: third_party/WebKit/Source/web/WebAXObject.cpp
diff --git a/third_party/WebKit/Source/web/WebAXObject.cpp b/third_party/WebKit/Source/web/WebAXObject.cpp
index 18b82a2567520e7fe9342e589acb7d8b3358b80f..186799b8ec0ec2334bff654503d7ba31b7e4551e 100644
--- a/third_party/WebKit/Source/web/WebAXObject.cpp
+++ b/third_party/WebKit/Source/web/WebAXObject.cpp
@@ -49,6 +49,7 @@
 #include "modules/accessibility/AXTableColumn.h"
 #include "modules/accessibility/AXTableRow.h"
 #include "platform/PlatformKeyboardEvent.h"
+#include "public/platform/WebFloatRect.h"
 #include "public/platform/WebPoint.h"
 #include "public/platform/WebRect.h"
 #include "public/platform/WebString.h"
@@ -1527,6 +1528,22 @@ void WebAXObject::setScrollOffset(const WebPoint& offset) const
     m_private->setScrollOffset(offset);
 }
 
+void WebAXObject::getRelativeBounds(WebAXObject& offsetContainer, WebFloatRect& boundsInContainer, SkMatrix44& containerTransform) const
+{
+    if (isDetached())
+        return;
+
+#if DCHECK_IS_ON()
+    DCHECK(isLayoutClean(m_private->getDocument()));
+#endif
+
+    AXObject* container = nullptr;
+    FloatRect bounds;
+    m_private->getRelativeBounds(&container, bounds, containerTransform);
+    offsetContainer = WebAXObject(container);
+    boundsInContainer = WebFloatRect(bounds);
+}
+
 void WebAXObject::scrollToMakeVisible() const
 {
     if (!isDetached())