Create errors (especially cancellation errors) internally to WebCore, rather

Source/WebCore/loader/FrameLoader.cpp

Index: Source/WebCore/loader/FrameLoader.cpp
===================================================================
--- Source/WebCore/loader/FrameLoader.cpp	(revision 148494)
+++ Source/WebCore/loader/FrameLoader.cpp	(working copy)
@@ -42,6 +42,7 @@
 #include "MemoryCache.h"
 #include "CachedPage.h"
 #include "CachedResourceLoader.h"
+#include "CancelledResourceError.h"
 #include "Chrome.h"
 #include "ChromeClient.h"
 #include "Console.h"
@@ -2504,7 +2505,9 @@
     // FIXME: Don't want to do this if an entirely new load is going, so should check
     // that both data sources on the frame are either this or nil.
     stop();
-    if (m_client->shouldFallBack(error))
+
+    ResourceError c = CancelledResourceError(KURL());

[darin (slow to review), 2013/04/17 18:58:11]

nit: CancelledResourceError c(KURL());

Although, reading the implementation of shouldFallBack makes me think that
perhaps you should instead just check the isCancellation() method.

[Nate Chapin, 2013/04/17 20:45:05]

I tried the switch to isCancellation(), and a couple of tests broke. I think
making that work is a good idea, but not today.

+    if (error.errorCode() != c.errorCode() || error.domain() != c.domain())
         handleFallbackContent();
 
     if (m_state == FrameStateProvisional && m_provisionalDocumentLoader) {
@@ -2770,7 +2773,7 @@
     notifier()->dispatchWillSendRequest(m_documentLoader.get(), identifier, newRequest, ResourceResponse());
 
     if (newRequest.isNull())
-        error = cancelledError(request);
+        error = CancelledResourceError(request.url());

[darin (slow to review), 2013/04/17 18:58:11]

Hmm, this relies on the fact that CancelledResourceError doesn't add any member
variables.  Perhaps usage like this is enough to suggest that
CancelledResourceError should instead be a function that returns ResourceError. 
Otherwise, we probably need to add a warning comment to CancelledResourceError
indicating that it would be a mistake to add member variables or virtual
functions to the class.

Sorry, when I suggested using a subclass, I hadn't considered this usage
pattern.

     else
         error = ResourceError();
 
@@ -3046,13 +3049,6 @@
         loadDifferentDocumentItem(item, loadType, MayAttemptCacheOnlyLoadForFormSubmissionItem);
 }
 
-ResourceError FrameLoader::cancelledError(const ResourceRequest& request) const
-{
-    ResourceError error = m_client->cancelledError(request);
-    error.setIsCancellation(true);
-    return error;
-}
-
 void FrameLoader::setTitle(const StringWithDirection& title)
 {
     documentLoader()->setTitle(title);