Add Mojo API for Blink hit testing

third_party/WebKit/public/web/WebWidget.h

Index: third_party/WebKit/public/web/WebWidget.h
diff --git a/third_party/WebKit/public/web/WebWidget.h b/third_party/WebKit/public/web/WebWidget.h
index 2a3465575b1afb106e0413c2e3445b9d3c1d1732..3c19333eb1694c36f179d99372412f7d750675ed 100644
--- a/third_party/WebKit/public/web/WebWidget.h
+++ b/third_party/WebKit/public/web/WebWidget.h
@@ -34,6 +34,7 @@
 #include "public/platform/WebBrowserControlsState.h"
 #include "public/platform/WebCanvas.h"
 #include "public/platform/WebCommon.h"
+#include "public/platform/WebFloatPoint.h"
 #include "public/platform/WebFloatSize.h"
 #include "public/platform/WebInputEventResult.h"
 #include "public/platform/WebMenuSourceType.h"
@@ -42,6 +43,7 @@
 #include "public/platform/WebSize.h"
 #include "public/platform/WebTextInputInfo.h"
 #include "public/web/WebCompositionUnderline.h"
+#include "public/web/WebHitTestResult.h"
 #include "public/web/WebRange.h"
 #include "public/web/WebTextDirection.h"
 
@@ -119,6 +121,11 @@ class WebWidget {
   // on receiving this message
   virtual void ThemeChanged() {}
 
+  // Do a hit test at given point and return the WebHitTestResult.
+  virtual WebHitTestResult HitTestResultAt(const WebPoint&) {
+    return WebHitTestResult();
+  }
+
   // Called to inform the WebWidget of an input event.
   virtual WebInputEventResult HandleInputEvent(const WebCoalescedInputEvent&) {
     return WebInputEventResult::kNotHandled;