Introduce ERR_NETWORK_CHANGED and allow URLFetcher to automatically retry on that error.

net/url_request/url_fetcher_impl.cc

Index: net/url_request/url_fetcher_impl.cc
diff --git a/net/url_request/url_fetcher_impl.cc b/net/url_request/url_fetcher_impl.cc
index 0fe1bfaf88ea76cad9c83752d6bbf3f68ff9c5ab..cdbd104f204079f46acffe2c21df32247008439b 100644
--- a/net/url_request/url_fetcher_impl.cc
+++ b/net/url_request/url_fetcher_impl.cc
@@ -89,12 +89,12 @@ void URLFetcherImpl::SetAutomaticallyRetryOn5xx(bool retry) {
   core_->SetAutomaticallyRetryOn5xx(retry);
 }
 
-void URLFetcherImpl::SetMaxRetries(int max_retries) {
-  core_->SetMaxRetries(max_retries);
+void URLFetcherImpl::SetMaxRetriesOn5xx(int max_retries) {
+  core_->SetMaxRetriesOn5xx(max_retries);
 }
 
-int URLFetcherImpl::GetMaxRetries() const {
-  return core_->GetMaxRetries();
+int URLFetcherImpl::GetMaxRetriesOn5xx() const {
+  return core_->GetMaxRetriesOn5xx();
 }
 
 
@@ -102,6 +102,10 @@ base::TimeDelta URLFetcherImpl::GetBackoffDelay() const {
   return core_->GetBackoffDelay();
 }
 
+void URLFetcherImpl::SetAutomaticallyRetryOnNetworkChanges(int max_retries) {
+  core_->SetAutomaticallyRetryOnNetworkChanges(max_retries);
+}
+
 void URLFetcherImpl::SaveResponseToFileAtPath(
     const FilePath& file_path,
     scoped_refptr<base::TaskRunner> file_task_runner) {