Reduce the amount of included header files. Vast change like in "Oh God! This...

net/url_request/url_request_context.h

Index: net/url_request/url_request_context.h
===================================================================
--- net/url_request/url_request_context.h	(revision 9942)
+++ net/url_request/url_request_context.h	(working copy)
@@ -15,9 +15,9 @@
 #include "base/string_util.h"
 #include "net/base/cookie_policy.h"
 #include "net/ftp/ftp_auth_cache.h"
-#include "net/http/http_transaction_factory.h"
 
 namespace net {
+class HttpTransactionFactory;
 class CookieMonster;
 class ProxyService;
 }