Make ResourceFetcher return Resources with LoadError instead of nullptrs.

third_party/WebKit/Source/core/fetch/Resource.cpp

Index: third_party/WebKit/Source/core/fetch/Resource.cpp
diff --git a/third_party/WebKit/Source/core/fetch/Resource.cpp b/third_party/WebKit/Source/core/fetch/Resource.cpp
index 579a3667325526cc532e4db23babe049d21f3385..c34d45fe3194eba5dcf8ff78a81cdcdd6164d8bc 100644
--- a/third_party/WebKit/Source/core/fetch/Resource.cpp
+++ b/third_party/WebKit/Source/core/fetch/Resource.cpp
@@ -638,7 +638,7 @@ void Resource::didAddClient(ResourceClient* c)
     }
 }
 
-static bool shouldSendCachedDataSynchronouslyForType(Resource::Type type)
+static bool typeNeedsSynchronousCacheHit(Resource::Type type)
 {
     // Some resources types default to return data synchronously.
     // For most of these, it's because there are layout tests that
@@ -688,8 +688,8 @@ void Resource::addClient(ResourceClient* client, PreloadReferencePolicy policy)
         return;
     }
 
-    // If we have existing data to send to the new client and the resource type supprts it, send it asynchronously.
-    if (!m_response.isNull() && !shouldSendCachedDataSynchronouslyForType(getType()) && !m_needsSynchronousCacheHit) {
+    // If an error has occurred or we have existing data to send to the new client and the resource type supprts it, send it asynchronously.
+    if ((errorOccurred() || !m_response.isNull()) && !typeNeedsSynchronousCacheHit(getType()) && !m_needsSynchronousCacheHit) {
         m_clientsAwaitingCallback.add(client);
         ResourceCallback::callbackHandler().schedule(this);
         return;