Fix a crash in the code which attempts to append the user agent to the list of outgoing

headers in ChromeFrame sub requests. The crash occurs because the current headers passed
in the BeginningTransaction are NULL.

Fixes bug http://code.google.com/p/chromium/issues/detail?id=62853

Bug=62853

Review URL: http://codereview.chromium.org/4792002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@65834 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 15 insertions, 14 deletions

diff --git a/chrome_frame/http_negotiate.cc b/chrome_frame/http_negotiate.cc
index 9d8344e..aea995a 100644
--- a/chrome_frame/http_negotiate.cc
+++ b/chrome_frame/http_negotiate.cc
@@ -135,22 +135,23 @@ std::string ReplaceOrAddUserAgent(LPCWSTR headers,
   DCHECK(headers);
   using net::HttpUtil;
 
-  std::string ascii_headers(WideToASCII(headers));
-
-  // Extract "User-Agent" from the headers.
-  HttpUtil::HeadersIterator headers_iterator(ascii_headers.begin(),
-                                             ascii_headers.end(), "\r\n");
-
-  // Build new headers, skip the existing user agent value from
-  // existing headers.
-  std::string new_headers;
-  while (headers_iterator.GetNext()) {
-    std::string name(headers_iterator.name());
-    if (!LowerCaseEqualsASCII(name, kLowerCaseUserAgent)) {
-      new_headers += name + ": " + headers_iterator.values() + "\r\n";
+  if (headers) {
+    std::string ascii_headers(WideToASCII(headers));
+
+    // Extract "User-Agent" from the headers.
+    HttpUtil::HeadersIterator headers_iterator(ascii_headers.begin(),
+                                               ascii_headers.end(), "\r\n");
+
+    // Build new headers, skip the existing user agent value from
+    // existing headers.
+    std::string new_headers;
+    while (headers_iterator.GetNext()) {
+      std::string name(headers_iterator.name());
+      if (!LowerCaseEqualsASCII(name, kLowerCaseUserAgent)) {
+        new_headers += name + ": " + headers_iterator.values() + "\r\n";
+      }
     }
   }
-
   new_headers += "User-Agent: " + user_agent_value;
   new_headers += "\r\n";
   return new_headers;