REGRESSION(r157081): Fix multipart handling of ResourceFetcher

Source/core/loader/DocumentLoader.cpp

Index: Source/core/loader/DocumentLoader.cpp
diff --git a/Source/core/loader/DocumentLoader.cpp b/Source/core/loader/DocumentLoader.cpp
index e57453a91dbb40af78a00c064845f893fed506fb..b55829f1151a7040cd32bf61c68d7975493428d0 100644
--- a/Source/core/loader/DocumentLoader.cpp
+++ b/Source/core/loader/DocumentLoader.cpp
@@ -188,6 +188,8 @@ void DocumentLoader::stopLoading()
             m_frame->loader().stopLoading();
     }
 
+    m_fetcher->stopFetching();
+
     if (!loading)
         return;
 
@@ -203,8 +205,6 @@ void DocumentLoader::stopLoading()
         // (A back/forward navigation has no resource loaders because its resources are cached.)
         mainReceivedError(ResourceError::cancelledError(m_request.url()));
     }
-
-    m_fetcher->stopFetching();
 }
 
 void DocumentLoader::commitIfReady()