Add Mojo API for Blink hit testing

third_party/WebKit/Source/core/frame/WebViewFrameWidget.cpp

Index: third_party/WebKit/Source/core/frame/WebViewFrameWidget.cpp
diff --git a/third_party/WebKit/Source/core/frame/WebViewFrameWidget.cpp b/third_party/WebKit/Source/core/frame/WebViewFrameWidget.cpp
index aa88b0082849e45f5e664be40abb462d5b6fd136..e48fd63a2c4c52cb727a9d1d89f0aaf8ca3c52ba 100644
--- a/third_party/WebKit/Source/core/frame/WebViewFrameWidget.cpp
+++ b/third_party/WebKit/Source/core/frame/WebViewFrameWidget.cpp
@@ -88,6 +88,10 @@ void WebViewFrameWidget::ThemeChanged() {
   return web_view_->ThemeChanged();
 }
 
+WebFrame* WebViewFrameWidget::HitTestFrameAt(const WebFloatPoint& point) {
+  return web_view_->HitTestFrameAt(point);
+}
+
 WebInputEventResult WebViewFrameWidget::HandleInputEvent(
     const WebCoalescedInputEvent& event) {
   return web_view_->HandleInputEvent(event);