Context menus should appear above the touch point if invoked by long press.

content/browser/web_contents/web_contents_view_gtk.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_GTK_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_GTK_H_
 
 #include <gtk/gtk.h>
 
 #include <vector>
@@ skipping 53 matching lines @@
   virtual void RestoreFocus() OVERRIDE;
   virtual bool IsDoingDrag() const OVERRIDE;
   virtual void CancelDragAndCloseTab() OVERRIDE;
   virtual WebDropData* GetDropData() const OVERRIDE;
   virtual bool IsEventTracking() const OVERRIDE;
   virtual void CloseTabAfterEventTracking() OVERRIDE;
   virtual gfx::Rect GetViewBounds() const OVERRIDE;
 
   // Backend implementation of RenderViewHostDelegateView.
   virtual void ShowContextMenu(
-      const content::ContextMenuParams& params) OVERRIDE;
+      const content::ContextMenuParams& params,
+      const content::ContextMenuSourceType& type) OVERRIDE;
   virtual void ShowPopupMenu(const gfx::Rect& bounds,
                              int item_height,
                              double item_font_size,
                              int selected_item,
                              const std::vector<WebMenuItem>& items,
                              bool right_aligned,
                              bool allow_multiple_selection) OVERRIDE;
   virtual void StartDragging(const WebDropData& drop_data,
                              WebKit::WebDragOperationsMask allowed_ops,
                              const gfx::ImageSkia& image,
@@ skipping 47 matching lines @@
   // The size we want the view to be.  We keep this in a separate variable
   // because resizing in GTK+ is async.
   gfx::Size requested_size_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsViewGtk);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_GTK_H_