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

chrome/default_plugin/plugin_installer_base.h

Index: chrome/default_plugin/plugin_installer_base.h
===================================================================
--- chrome/default_plugin/plugin_installer_base.h	(revision 0)
+++ chrome/default_plugin/plugin_installer_base.h	(revision 0)
@@ -0,0 +1,33 @@
+// 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.
+
+#ifndef CHROME_DEFAULT_PLUGIN_PLUGIN_INSTALLER_BASE_H_
+#define CHROME_DEFAULT_PLUGIN_PLUGIN_INSTALLER_BASE_H_
+
+#include "base/basictypes.h"
+#include "third_party/npapi/bindings/npapi.h"
+
+// Base class for the plugin installer.
+class PluginInstallerBase {
+ public:
+  PluginInstallerBase();
+  virtual ~PluginInstallerBase();
+
+  bool Initialize(void* module_handle, NPP instance, NPMIMEType mime_type,
+                  int16 argc, char* argn[], char* argv[]);
+
+  int renderer_process_id() const {
+    return renderer_process_id_;
+  }
+
+  int render_view_id() const {
+    return render_view_id_;
+  }
+
+ private:
+  int renderer_process_id_;
+  int render_view_id_;
+};
+
+#endif  // CHROME_DEFAULT_PLUGIN_PLUGIN_INSTALLER_BASE_H_