Add Mojo API for Blink hit testing

third_party/WebKit/Source/core/exported/WebNode.cpp

Index: third_party/WebKit/Source/core/exported/WebNode.cpp
diff --git a/third_party/WebKit/Source/core/exported/WebNode.cpp b/third_party/WebKit/Source/core/exported/WebNode.cpp
index a9cb9678f2e2564efe084943da15cf72f23b31da..17a6c066a3f6401beead4aa2a88d6ac22a07a26a 100644
--- a/third_party/WebKit/Source/core/exported/WebNode.cpp
+++ b/third_party/WebKit/Source/core/exported/WebNode.cpp
@@ -45,6 +45,7 @@
 #include "core/exported/WebPluginContainerImpl.h"
 #include "core/html/HTMLCollection.h"
 #include "core/html/HTMLElement.h"
+#include "core/html/HTMLFrameOwnerElement.h"
 #include "core/layout/LayoutEmbeddedContent.h"
 #include "core/layout/LayoutObject.h"
 #include "platform/wtf/PtrUtil.h"
@@ -99,6 +100,15 @@ WebDocument WebNode::GetDocument() const {
   return WebDocument(&private_->GetDocument());
 }
 
+WebFrame* WebNode::ContentFrame() const {
+  Frame* target_frame = nullptr;
+  if (private_->IsFrameOwnerElement())
+    target_frame = ToHTMLFrameOwnerElement(private_.Get())->ContentFrame();
+  else
+    target_frame = private_->GetDocument().GetFrame();
+  return WebFrame::FromFrame(target_frame);
+}
+
 WebNode WebNode::FirstChild() const {
   return WebNode(private_->firstChild());
 }