Add PluginInstaller to encapsulate information about a missing plug-in.

chrome/browser/plugin_installer.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.h"
+
+PluginInstaller::~PluginInstaller() {
+}
+
+PluginInstaller::PluginInstaller(const std::string& identifier,
+                                 const GURL& plugin_url,
+                                 const GURL& help_url,
+                                 const string16& name,
+                                 bool url_for_display)
+    : identifier_(identifier),
+      plugin_url_(plugin_url),
+      help_url_(help_url),
+      name_(name),
+      url_for_display_(url_for_display) {
+}