Move ContextMenuParams struct from webkit/glue to content/public/common. The reasons are:

content/renderer/pepper_plugin_delegate_impl.h

Index: content/renderer/pepper_plugin_delegate_impl.h
===================================================================
--- content/renderer/pepper_plugin_delegate_impl.h	(revision 121660)
+++ content/renderer/pepper_plugin_delegate_impl.h	(working copy)
@@ -33,6 +33,7 @@
 
 namespace content {
 class GamepadSharedMemoryReader;
+struct CustomContextMenuContext;
 }
 
 namespace gfx {
@@ -61,10 +62,6 @@
 struct WebFileChooserParams;
 }
 
-namespace webkit_glue {
-struct CustomContextMenuContext;
-}
-
 class TransportDIB;
 
 // This object is NOT thread-safe.
@@ -354,9 +351,9 @@
       webkit::ppapi::PPB_Flash_Menu_Impl* menu,
       const gfx::Point& position) OVERRIDE;
   void OnContextMenuClosed(
-      const webkit_glue::CustomContextMenuContext& custom_context);
+      const content::CustomContextMenuContext& custom_context);
   void OnCustomContextMenuAction(
-      const webkit_glue::CustomContextMenuContext& custom_context,
+      const content::CustomContextMenuContext& custom_context,
       unsigned action);
   void CompleteShowContextMenu(int request_id,
                                bool did_select,