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

Source/core/loader/FrameLoaderClient.h

Index: Source/core/loader/FrameLoaderClient.h
diff --git a/Source/core/loader/FrameLoaderClient.h b/Source/core/loader/FrameLoaderClient.h
index 6044ccab25efa378cbf0149c739a3df9ed4daf02..897d54a4f08605febc30dd7b86f7ab98d7f20c70 100644
--- a/Source/core/loader/FrameLoaderClient.h
+++ b/Source/core/loader/FrameLoaderClient.h
@@ -123,6 +123,8 @@ namespace WebCore {
         virtual PolicyAction policyForNewWindowAction(const NavigationAction&, const String& frameName) = 0;
         virtual PolicyAction decidePolicyForNavigationAction(const NavigationAction&, const ResourceRequest&) = 0;
 
+        virtual void dispatchUnableToImplementPolicy(const ResourceError&) = 0;
+
         virtual void dispatchWillRequestResource(CachedResourceRequest*) { }
 
         virtual void dispatchWillSendSubmitEvent(PassRefPtr<FormState>) = 0;
@@ -163,7 +165,17 @@ namespace WebCore {
         virtual void didRunInsecureContent(SecurityOrigin*, const KURL&) = 0;
         virtual void didDetectXSS(const KURL&, bool didBlockEntirePage) = 0;
 
+        virtual ResourceError cancelledError(const ResourceRequest&) = 0;
+        virtual ResourceError cannotShowURLError(const ResourceRequest&) = 0;
         virtual ResourceError interruptedForPolicyChangeError(const ResourceRequest&) = 0;
+
+        virtual ResourceError cannotShowMIMETypeError(const ResourceResponse&) = 0;
+        virtual ResourceError fileDoesNotExistError(const ResourceResponse&) = 0;
+        virtual ResourceError pluginWillHandleLoadError(const ResourceResponse&) = 0;
+
+        virtual bool shouldFallBack(const ResourceError&) = 0;
+
+        virtual bool canHandleRequest(const ResourceRequest&) const = 0;
         virtual bool canShowMIMEType(const String& MIMEType) const = 0;
         virtual String generatedMIMETypeForURLScheme(const String& URLScheme) const = 0;