Add the chromeframe tag to the user agent header at runtime instead of static...

chrome_frame/http_negotiate.h

+// Copyright (c) 2009 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_FRAME_HTTP_NEGOTIATE_H_
+#define CHROME_FRAME_HTTP_NEGOTIATE_H_
+
+#include <urlmon.h>
+
+#include "base/basictypes.h"
+
+// Typedefs for IHttpNegotiate methods.
+typedef HRESULT (STDMETHODCALLTYPE* IHttpNegotiate_BeginningTransaction_Fn)(
+    IHttpNegotiate* me, LPCWSTR url, LPCWSTR headers, DWORD reserved,
+    LPWSTR* additional_headers);
+typedef HRESULT (STDMETHODCALLTYPE* IHttpNegotiate_OnResponse_Fn)(
+    IHttpNegotiate* me, DWORD response_code, LPCWSTR response_header,
+    LPCWSTR request_header, LPWSTR* additional_request_headers);
+
+// Patches methods of urlmon's IHttpNegotiate implementation for the purposes
+// of adding to the http user agent header.
+class HttpNegotiatePatch {
+  // class is not to be instantiated atm.
+  HttpNegotiatePatch();
+  ~HttpNegotiatePatch();
+
+ public:
+  static bool Initialize();
+  static void Uninitialize();
+
+  static STDMETHODIMP BeginningTransaction(
+      IHttpNegotiate_BeginningTransaction_Fn original, IHttpNegotiate* me,
+      LPCWSTR url, LPCWSTR headers, DWORD reserved, LPWSTR* additional_headers);
+
+  static STDMETHODIMP OnResponse(
+      IHttpNegotiate_OnResponse_Fn original, IHttpNegotiate* me,
+      DWORD response_code, LPCWSTR response_header, LPCWSTR request_header,
+      LPWSTR* additional_request_headers);
+
+ protected:
+  static HRESULT PatchHttpNegotiate(IUnknown* to_patch);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(HttpNegotiatePatch);
+};
+
+#endif  // CHROME_FRAME_HTTP_NEGOTIATE_H_