Add support for chunked encoding in ChromeFrame for POST requests. This fixes...

chrome_frame/test/net/fake_external_tab.cc

Index: chrome_frame/test/net/fake_external_tab.cc
===================================================================
--- chrome_frame/test/net/fake_external_tab.cc	(revision 72649)
+++ chrome_frame/test/net/fake_external_tab.cc	(working copy)
@@ -461,6 +461,9 @@
     // This test is disabled as it expects an empty UA to be echoed back from
     // the server which is not the case in ChromeFrame.
     "URLRequestTestHTTP.DefaultUserAgent",
+    // This test modifies the UploadData object after it has been marshaled to
+    // ChromeFrame. We don't support this.
+    "URLRequestTestHTTP.TestPostChunkedDataAfterStart",
   };
 
   std::string filter("-");  // All following filters will be negative.