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

webkit/plugins/npapi/webplugin_delegate_impl_mac.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 #import <QuartzCore/QuartzCore.h>
 
 #include "webkit/plugins/npapi/webplugin_delegate_impl.h"
 
 #include <string>
@@ skipping 622 matching lines @@
     // shortcuts is not ideal.
     // TODO(stuartmorgan): Implement the advanced key handling spec, and trust
     // trust the key event return value from plugins that implement it.
     if (!(event.modifiers & WebInputEvent::MetaKey))
       handled = true;
   }
 
   return handled;
 }
 
-void WebPluginDelegateImpl::InstallMissingPlugin() {
-  NOTIMPLEMENTED();
-}
-
 #pragma mark -
 
 void WebPluginDelegateImpl::WindowlessUpdateGeometry(
     const gfx::Rect& window_rect,
     const gfx::Rect& clip_rect) {
   gfx::Rect old_clip_rect = clip_rect_;
   cached_clip_rect_ = clip_rect;
   if (container_is_visible_)  // Remove check when cached_clip_rect_ is removed.
     clip_rect_ = clip_rect;
   bool clip_rect_changed = (clip_rect_ != old_clip_rect);
@@ skipping 555 matching lines @@
   qd_manager_->SetFastPathEnabled(enabled);
   qd_port_.port = qd_manager_->port();
   WindowlessSetWindow();
   // Send a paint event so that the new buffer gets updated immediately.
   WindowlessPaint(buffer_context_, clip_rect_);
 }
 #endif  // !NP_NO_QUICKDRAW
 
 }  // namespace npapi
 }  // namespace webkit