Move NPAPI implementation out of webkit/plugins/npapi and into content.

webkit/plugins/npapi/gtk_plugin_container.h

-// Copyright (c) 2009 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 WEBKIT_PLUGINS_NPAPI_GTK_PLUGIN_CONTAINER_H_
-#define WEBKIT_PLUGINS_NPAPI_GTK_PLUGIN_CONTAINER_H_
-
-// Windowed plugins are embedded via XEmbed, which is implemented by
-// GtkPlug/GtkSocket.  But we want to control sizing and positioning
-// directly, so we need a subclass of GtkSocket that sidesteps the
-// size_request handler.
-//
-// The custom size_request handler just reports the size set by
-// gtk_plugin_container_set_size.
-
-typedef struct _GtkWidget GtkWidget;
-
-namespace webkit {
-namespace npapi {
-
-// Return a new GtkPluginContainer.
-// Intentionally GTK-style here since we're creating a custom GTK widget.
-// This is a GtkSocket subclass; see its documentation for available methods.
-GtkWidget* gtk_plugin_container_new();
-
-// Sets the size of the GtkPluginContainer.
-void gtk_plugin_container_set_size(GtkWidget *widget, int width, int height);
-
-}  // namespace npapi
-}  // namespace webkit
-
-#endif  // WEBKIT_PLUGINS_NPAPI_GTK_PLUGIN_CONTAINER_H_