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

google_apis/gaia/gaia_oauth_client.cc

Index: google_apis/gaia/gaia_oauth_client.cc
diff --git a/google_apis/gaia/gaia_oauth_client.cc b/google_apis/gaia/gaia_oauth_client.cc
index 46fbac166db1208a90814aa87fde72baa6bb4f00..1adefb8b19b3a124d747e009aa28edb7476d0fc5 100644
--- a/google_apis/gaia/gaia_oauth_client.cc
+++ b/google_apis/gaia/gaia_oauth_client.cc
@@ -128,7 +128,7 @@ void GaiaOAuthClient::Core::GetUserInfo(const std::string& oauth_access_token,
   request_->SetRequestContext(request_context_getter_);
   request_->AddExtraRequestHeader(
       "Authorization: OAuth " + oauth_access_token);
-  request_->SetMaxRetries(max_retries);
+  request_->SetMaxRetriesOn5xx(max_retries);
   request_->Start();
 }
 
@@ -143,7 +143,7 @@ void GaiaOAuthClient::Core::MakeGaiaRequest(
       0, gaia_url_, net::URLFetcher::POST, this));
   request_->SetRequestContext(request_context_getter_);
   request_->SetUploadData("application/x-www-form-urlencoded", post_body);
-  request_->SetMaxRetries(max_retries);
+  request_->SetMaxRetriesOn5xx(max_retries);
   request_->Start();
 }
 
@@ -195,8 +195,8 @@ void GaiaOAuthClient::Core::HandleResponse(
   if (!response_dict.get()) {
     // If we don't have an access token yet and the the error was not
     // RC_BAD_REQUEST, we may need to retry.
-    if ((source->GetMaxRetries() != -1) &&
-        (num_retries_ > source->GetMaxRetries())) {
+    if ((source->GetMaxRetriesOn5xx() != -1) &&
+        (num_retries_ > source->GetMaxRetriesOn5xx())) {
       // Retry limit reached. Give up.
       delegate_->OnNetworkError(source->GetResponseCode());
     } else {