Add Mojo API for Blink hit testing

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

Index: third_party/WebKit/Source/core/frame/WebViewFrameWidget.h
diff --git a/third_party/WebKit/Source/core/frame/WebViewFrameWidget.h b/third_party/WebKit/Source/core/frame/WebViewFrameWidget.h
index ef22d0d72daa5df2613074f5abfd1ce15cda359c..26de20f3b8b6887a6c2c92c21e8b13dc677e52a0 100644
--- a/third_party/WebKit/Source/core/frame/WebViewFrameWidget.h
+++ b/third_party/WebKit/Source/core/frame/WebViewFrameWidget.h
@@ -57,6 +57,7 @@ class CORE_EXPORT WebViewFrameWidget : public WebFrameWidgetBase {
   void CompositeAndReadbackAsync(
       WebCompositeAndReadbackAsyncCallback*) override;
   void ThemeChanged() override;
+  //  WebFrame* HitTestFrameAt(const WebFloatPoint&) override;
   WebInputEventResult HandleInputEvent(const WebCoalescedInputEvent&) override;
   void SetCursorVisibilityState(bool is_visible) override;
   bool HasTouchEventHandlersAt(const WebPoint&) override;
@@ -104,6 +105,7 @@ class CORE_EXPORT WebViewFrameWidget : public WebFrameWidgetBase {
   WebLayerTreeView* GetLayerTreeView() const override;
   CompositorAnimationHost* AnimationHost() const override;
   WebWidgetClient* Client() const override { return client_; }
+  WebHitTestResult HitTestResultAt(const WebPoint&) override;
   HitTestResult CoreHitTestResultAt(const WebPoint&) override;
 
   DECLARE_VIRTUAL_TRACE();