Add a setting to CF to remove 'chromeframe' from the UserAgent on a per-pattern basis.

chrome_frame/html_utils.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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_frame/html_utils.h"
 
 #include <atlbase.h>
 #include <urlmon.h>
 
 #include "base/string_util.h"
 #include "base/string_tokenizer.h"
@@ skipping 324 matching lines @@
                 HIWORD(high_version), LOWORD(high_version),
                 HIWORD(low_version), LOWORD(low_version));
     }
     _pAtlModule->m_csStaticDataInitAndTypeInfo.Unlock();
   }
   return g_cf_user_agent;
 }
 
 std::string AddChromeFrameToUserAgentValue(const std::string& value) {
   if (value.empty()) {
-    DLOG(WARNING) << "empty user agent value";
-    return "";
+    return value;
   }
 
-  DCHECK_EQ(false, StartsWithASCII(value, "User-Agent:", true));
-
   if (value.find(kChromeFrameUserAgent) != std::string::npos) {
     // Our user agent has already been added.
     return value;
   }
 
   std::string ret(value);
-  std::string::size_type insert_position = ret.find(')');
+  size_t insert_position = ret.find(')');
   if (insert_position != std::string::npos) {
     if (insert_position > 1 && isalnum(ret[insert_position - 1]))
       ret.insert(insert_position++, ";");
     ret.insert(insert_position++, " ");
     ret.insert(insert_position, GetChromeFrameUserAgent());
   } else {
     ret += " ";
     ret += GetChromeFrameUserAgent();
   }
 
   return ret;
 }
 
+std::string RemoveChromeFrameFromUserAgentValue(const std::string& value) {
+  size_t cf_start = value.find(kChromeFrameUserAgent);
+  if (cf_start == std::string::npos) {
+    // The user agent is not present.
+    return value;
+  }
+
+  size_t offset = 0;
+  // If we prepended a '; ' or a ' ' then remove that in the output.
+  if (cf_start > 1 && value[cf_start - 1] == ' ')
+    ++offset;
+  if (cf_start > 3 &&
+      value[cf_start - 2] == ';' &&
+      isalnum(value[cf_start - 3])) {
+    ++offset;
+  }
+
+  std::string ret(value, 0, std::max(cf_start - offset, 0U));
+  cf_start += strlen(kChromeFrameUserAgent);
+  while (cf_start < value.length() &&
+         ((value[cf_start] >= '0' && value[cf_start] <= '9') ||
+          value[cf_start] == '.' ||
+          value[cf_start] == '/')) {
+    ++cf_start;
+  }
+
+  if (cf_start < value.length())
+    ret.append(value, cf_start, std::string::npos);
+
+  return ret;
+}
+
 std::string GetDefaultUserAgentHeaderWithCFTag() {
   std::string ua(GetDefaultUserAgent());
   return "User-Agent: " + AddChromeFrameToUserAgentValue(ua);
 }
 
 const char* GetChromeUserAgent() {
   if (!g_chrome_user_agent[0]) {
     _pAtlModule->m_csStaticDataInitAndTypeInfo.Lock();
     if (!g_chrome_user_agent[0]) {
       std::string ua;
@@ skipping 55 matching lines @@
                                         const std::string& headers) {
   net::HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\r\n");
   while (it.GetNext()) {
     if (!lstrcmpiA(it.name().c_str(), header.c_str()))
       return std::string(it.values_begin(), it.values_end());
   }
   return std::string();
 }
 
 }  // namespace http_utils