Moved the following IPC messages used by the chrome NPAPI plugin installer out of content

webkit/plugins/npapi/webplugin_delegate_impl_gtk.cc

 // Copyright (c) 2011 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.
 
 #include "webkit/plugins/npapi/webplugin_delegate_impl.h"
 
 #include <string>
 #include <vector>
 
 #include <gtk/gtk.h>
@@ skipping 98 matching lines @@
 
 void WebPluginDelegateImpl::Paint(WebKit::WebCanvas* canvas,
                                   const gfx::Rect& rect) {
   if (!windowless_)
     return;
   skia::ScopedPlatformPaint scoped_platform_paint(canvas);
   cairo_t* context = scoped_platform_paint.GetPlatformSurface();
   WindowlessPaint(context, rect);
 }
 
-void WebPluginDelegateImpl::InstallMissingPlugin() {
-  NOTIMPLEMENTED();
-}
-
 bool WebPluginDelegateImpl::WindowedCreatePlugin() {
   DCHECK(!windowed_handle_);
   DCHECK(!plug_);
 
   // NPP_GetValue() might write 4 bytes of data to this variable.  Don't use a
   // single byte bool, use an int instead and make sure it is initialized.
   int xembed = 0;
   NPError err = instance_->NPP_GetValue(NPPVpluginNeedsXEmbed, &xembed);
   if (err != NPERR_NO_ERROR || !xembed) {
     NOTIMPLEMENTED() << " windowed plugin but without xembed. "
@@ skipping 626 matching lines @@
     // as someone might be setting the cursor in the main process as well.
     *cursor = current_windowless_cursor_;
   }
 #endif
 
   return ret;
 }
 
 }  // namespace npapi
 }  // namespace webkit