Structured cloning: improve DataCloneError reporting.

Source/bindings/v8/ExceptionState.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 88 matching lines @@
         }
 
         V8ThrowException::throwError(m_exception.newLocal(m_isolate), m_isolate);
         return true;
     }
 
     Context context() const { return m_context; }
     const char* propertyName() const { return m_propertyName; }
     const char* interfaceName() const { return m_interfaceName; }
 
+    void setException(v8::Handle<v8::Value>);

[Mike West, 2013/12/13 21:22:59]

Why is this now public? I don't see where you need to use it outside
ExceptionState.

[sof, 2013/12/13 21:51:33]

It's used to transfer the exception from the TryCatch in
SerializedScriptValue::SerializedScriptValue() --

 https://codereview.chromium.org/114363002/patch/1/10024

It gave me pause to do so, but I thought it fairly reasonable to have a public
ExceptionState method for setting a pre-constructed exception value also.

[Dmitry Lomov (no reviews), 2013/12/16 09:14:39]

I think the naming of methods on ExceptionState is confusing. All
'throw*Exception' methods do not actually throw, they just set the state on
ExceptionState. The only method that actually throws is 'throwIfNeeded'. 
If we follow this, a bit confusing, state of the API, the good name for a public
'setException' would be 'rethrowV8Exception' (throwIfNeeded will just propagate
the exception).

In the long run, I suggest renaming all 'throw*Exception' => 'report*Exception'

+
 protected:
     ExceptionCode m_code;
     Context m_context;
     const char* m_propertyName;
     const char* m_interfaceName;
 
 private:
-    void setException(v8::Handle<v8::Value>);
-
     String addExceptionContext(const String&) const;
 
     ScopedPersistent<v8::Value> m_exception;
     v8::Handle<v8::Object> m_creationContext;
     v8::Isolate* m_isolate;
 };
 
 class TrackExceptionState : public ExceptionState {
 public:
     TrackExceptionState(): ExceptionState(v8::Handle<v8::Object>(), 0) { }
     virtual void throwDOMException(const ExceptionCode&, const String& message) OVERRIDE FINAL;
     virtual void throwTypeError(const String& message = String()) OVERRIDE FINAL;
     virtual void throwSecurityError(const String& sanitizedMessage, const String& unsanitizedMessage = String()) OVERRIDE FINAL;
 };
 
 } // namespace WebCore
 
 #endif // ExceptionState_h