Notify when resource with error code >= 400 is finished.

Source/core/fetch/ResourceLoader.cpp

Index: Source/core/fetch/ResourceLoader.cpp
diff --git a/Source/core/fetch/ResourceLoader.cpp b/Source/core/fetch/ResourceLoader.cpp
index 0d2d6c42ed04fc51e7f457bb0548394533e55709..5d15c81739858d5360703015f50533897cfbc505 100644
--- a/Source/core/fetch/ResourceLoader.cpp
+++ b/Source/core/fetch/ResourceLoader.cpp
@@ -86,6 +86,7 @@ ResourceLoader::~ResourceLoader()
 
 void ResourceLoader::releaseResources()
 {
+    ASSERT(m_notifiedLoadComplete);
     ASSERT(m_state != Terminated);
     m_requestCountTracker.clear();
     m_host->didLoadResource(m_resource);
@@ -247,7 +248,10 @@ void ResourceLoader::cancel(const ResourceError& error)
         m_loader.clear();
     }
 
-    m_host->didFailLoading(m_resource, nonNullError);
+    if (!m_notifiedLoadComplete) {
+        m_notifiedLoadComplete = true;
+        m_host->didFailLoading(m_resource, nonNullError);
+    }
 
     if (m_state == Finishing)
         m_resource->error(Resource::LoadError);
@@ -352,8 +356,13 @@ void ResourceLoader::didReceiveResponse(blink::WebURLLoader*, const blink::WebUR
 
     if (m_resource->response().httpStatusCode() < 400 || m_resource->shouldIgnoreHTTPStatusCodeErrors())
         return;
+
     m_state = Finishing;
     m_resource->error(Resource::LoadError);
+    if (!m_notifiedLoadComplete) {

[Nate Chapin, 2014/01/31 17:25:52]

I'm not sure this is safe. Specifically, if m_resource->error() triggers an
event, it's possible that this ResourceLoader will get cancelled synchronously
inside. If that happens, because m_state is already Finishing, cancel() will
call releaseResources() and clear m_host without setting m_notifiedLoadComplete
to true.

I suspect that here and throughout, we should make sure the
m_host->didFinishLoading() or m_host->didFailLoading() call happens before the
m_resource->finish() or m_resource->error().

[eustas, 2014/02/03 12:56:06]

Done.

+        m_notifiedLoadComplete = true;
+        m_host->didFinishLoading(m_resource, monotonicallyIncreasingTime());
+    }
     cancel();
 }