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

Source/core/platform/network/ResourceError.h

Index: Source/core/platform/network/ResourceError.h
diff --git a/Source/core/platform/network/ResourceError.h b/Source/core/platform/network/ResourceError.h
index 0685f7bebeed368a8daaede942c78ddbe0533e4d..47439ef8d88a81129860570c63f4a1c86e882362 100644
--- a/Source/core/platform/network/ResourceError.h
+++ b/Source/core/platform/network/ResourceError.h
@@ -35,8 +35,6 @@ extern const char* const errorDomainWebKitInternal; // Used for errors that won'
 
 class ResourceError {
 public:
-    static ResourceError cancelledError(const String& failingURL);
-
     ResourceError()
         : m_errorCode(0)
         , m_isNull(true)