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

chrome/browser/plugin_installer_infobar_delegate.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 "chrome/browser/plugin_installer_infobar_delegate.h"
 
 #include "chrome/browser/google/google_util.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/common/view_messages.h"
 #include "grit/generated_resources.h"
 #include "grit/locale_settings.h"
 #include "grit/theme_resources_standard.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "webkit/plugins/npapi/default_plugin_shared.h"
 
 PluginInstallerInfoBarDelegate::PluginInstallerInfoBarDelegate(
-    TabContents* tab_contents)
+    TabContents* tab_contents, gfx::NativeWindow window)
     : ConfirmInfoBarDelegate(tab_contents),
-      tab_contents_(tab_contents) {
+      tab_contents_(tab_contents),
+      window_(window) {
 }
 
 PluginInstallerInfoBarDelegate::~PluginInstallerInfoBarDelegate() {
 }
 
 gfx::Image* PluginInstallerInfoBarDelegate::GetIcon() const {
   return &ResourceBundle::GetSharedInstance().GetNativeImageNamed(
       IDR_INFOBAR_PLUGIN_INSTALL);
 }
 
@@ skipping 10 matching lines @@
   return BUTTON_OK;
 }
 
 string16 PluginInstallerInfoBarDelegate::GetButtonLabel(
     InfoBarButton button) const {
   DCHECK_EQ(BUTTON_OK, button);
   return l10n_util::GetStringUTF16(IDS_PLUGININSTALLER_INSTALLPLUGIN_BUTTON);
 }
 
 bool PluginInstallerInfoBarDelegate::Accept() {
-  RenderViewHost* host = tab_contents_->render_view_host();
-  host->Send(new ViewMsg_InstallMissingPlugin(host->routing_id()));
+  // TODO(PORT) for other platforms.
+#ifdef OS_WIN
+  ::PostMessage(window_,
+                webkit::npapi::default_plugin::kInstallMissingPluginMessage,
+                0,
+                0);
+#endif  // OS_WIN
   return true;
 }
 
 string16 PluginInstallerInfoBarDelegate::GetLinkText() const {
   return l10n_util::GetStringUTF16(IDS_PLUGININSTALLER_PROBLEMSINSTALLING);
 }
 
 bool PluginInstallerInfoBarDelegate::LinkClicked(
     WindowOpenDisposition disposition) {
   tab_contents_->OpenURL(google_util::AppendGoogleLocaleParam(GURL(
       "http://www.google.com/support/chrome/bin/answer.py?answer=95697&topic="
       "14687")), GURL(),
       (disposition == CURRENT_TAB) ? NEW_FOREGROUND_TAB : disposition,
       PageTransition::LINK);
   return false;
 }