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

chrome/default_plugin/plugin_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.
 
 #include "chrome/default_plugin/plugin_impl_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/string_util.h"
+#include "chrome/common/chrome_plugin_messages.h"
 #include "chrome/default_plugin/plugin_main.h"
+#include "content/common/child_thread.h"
 #include "googleurl/src/gurl.h"
 #include "grit/default_plugin_resources.h"
 #include "grit/webkit_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 #include "unicode/locid.h"
 #include "webkit/glue/webkit_glue.h"
@@ skipping 25 matching lines @@
 
   instance_ = instance;
   mime_type_ = mime_type;
 
   command_ = [l10n_util::FixUpWindowsStyleLabel(l10n_util::GetStringUTF16(
       IDS_DEFAULT_PLUGIN_NO_PLUGIN_AVAILABLE_MSG)) retain];
 
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   image_ = rb.GetNativeImageNamed(IDR_PLUGIN_ICON);
 
-  return true;
+  return PluginInstallerBase::Initialize(module_handle, instance, mime_type,
+                                         argc, argn, argv);
 }
 
 bool PluginInstallerImpl::NPP_SetWindow(NPWindow* window_info) {
   width_ = window_info->width;
   height_ = window_info->height;
   return true;
 }
 
 void PluginInstallerImpl::Shutdown() {
 }
@@ skipping 116 matching lines @@
   [command_ drawAtPoint:label_point withAttributes:attributes];
 
   return 1;
 }
 
 
 void PluginInstallerImpl::ShowInstallDialog() {
 }
 
 void PluginInstallerImpl::NotifyPluginStatus(int status) {
-  default_plugin::g_browser->getvalue(
-      instance_,
-      static_cast<NPNVariable>(
-          webkit::npapi::default_plugin::kMissingPluginStatusStart + status),
-      NULL);
+  ChildThread::current()->Send(
+      new ChromePluginProcessHostMsg_MissingPluginStatus(
+          status,
+          renderer_process_id(),
+          render_view_id(),
+          0));
 }