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

chrome/default_plugin/plugin_installer_base.cc

Index: chrome/default_plugin/plugin_installer_base.cc
===================================================================
--- chrome/default_plugin/plugin_installer_base.cc	(revision 0)
+++ chrome/default_plugin/plugin_installer_base.cc	(revision 0)
@@ -0,0 +1,34 @@
+// 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_installer_base.h"
+
+#include "base/string_number_conversions.h"
+#include "base/string_util.h"
+#include "content/common/content_constants.h"
+
+PluginInstallerBase::PluginInstallerBase()
+    : renderer_process_id_(0),
+      render_view_id_(0) {
+}
+
+PluginInstallerBase::~PluginInstallerBase() {
+}
+
+bool PluginInstallerBase::Initialize(void* module_handle, NPP instance,
+                                     NPMIMEType mime_type, int16 argc,
+                                     char* argn[], char* argv[]) {
+  for (int16_t index = 0; index < argc; ++index) {
+    if (!base::strncasecmp(argn[index],
+                           content::kDefaultPluginRenderProcessId,
+                           strlen(argn[index]))) {
+      base::StringToInt(argv[index], &renderer_process_id_);
+    } else if (!base::strncasecmp(argn[index],
+                                  content::kDefaultPluginRenderViewId,
+                                  strlen(argn[index]))) {
+      base::StringToInt(argv[index], &render_view_id_);
+    }
+  }
+  return true;
+}