Don't pass SDCH GetDictionary event for cached responses

net/url_request/url_request_http_job.cc

Index: net/url_request/url_request_http_job.cc
diff --git a/net/url_request/url_request_http_job.cc b/net/url_request/url_request_http_job.cc
index 47a0666e3fc7ad50225110e7f394da8adf08c83c..9a051701a6939c98e47e62b87ba39ecffdab81ec 100644
--- a/net/url_request/url_request_http_job.cc
+++ b/net/url_request/url_request_http_job.cc
@@ -366,7 +366,9 @@ void URLRequestHttpJob::NotifyHeadersComplete() {
       if (GetResponseHeaders()->EnumerateHeader(&iter, name, &url_text)) {
         // Resolve suggested URL relative to request url.
         GURL sdch_dictionary_url = request_->url().Resolve(url_text);
-        if (sdch_dictionary_url.is_valid()) {
+        // Don't try to download Dictionary for cached responses. It's either
+        // useless or too late.
+        if (sdch_dictionary_url.is_valid() && !is_cached_content_) {
           rv = sdch_manager->OnGetDictionary(request_->url(),
                                              sdch_dictionary_url);
           if (rv != SDCH_OK) {