Add Mojo API for Blink hit testing

third_party/WebKit/public/web/WebView.h

 /*
  * Copyright (C) 2009, 2010, 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 72 matching lines @@
   using WebWidget::ResizeVisualViewport;
   using WebWidget::DidEnterFullscreen;
   using WebWidget::DidExitFullscreen;
   using WebWidget::BeginFrame;
   using WebWidget::UpdateAllLifecyclePhases;
   using WebWidget::Paint;
   using WebWidget::PaintIgnoringCompositing;
   using WebWidget::LayoutAndPaintAsync;
   using WebWidget::CompositeAndReadbackAsync;
   using WebWidget::ThemeChanged;
+  using WebWidget::HitTestFrameAt;
   using WebWidget::HandleInputEvent;
   using WebWidget::SetCursorVisibilityState;
   using WebWidget::HasTouchEventHandlersAt;
   using WebWidget::ApplyViewportDeltas;
   using WebWidget::MouseCaptureLost;
   using WebWidget::SetFocus;
   using WebWidget::CompositionRange;
   using WebWidget::SelectionBounds;
   using WebWidget::SelectionTextDirection;
   using WebWidget::IsSelectionAnchorFirst;
@@ skipping 369 matching lines @@
   // completed.
   WebWidget* GetWidget() { return this; }
 
  protected:
   ~WebView() {}
 };
 
 }  // namespace blink
 
 #endif