Use auto-rethrowing v8::TryCatch variant

Source/bindings/v8/V8Binding.h

 /*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 * Copyright (C) 2012 Ericsson AB. 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.
@@ skipping 922 matching lines @@
 
 private:
     v8::HandleScope m_handleScope;
     v8::Context::Scope m_contextScope;
     RefPtr<ScriptState> m_scriptState;
 };
 
 void GetDevToolsFunctionInfo(v8::Handle<v8::Function>, v8::Isolate*, int& scriptId, String& resourceName, int& lineNumber);
 PassRefPtr<TraceEvent::ConvertableToTraceFormat> devToolsTraceEventData(ExecutionContext*, v8::Handle<v8::Function>, v8::Isolate*);
 
+// TryCatch variant that automatically rethrows caught exceptions.
+// Useful for cases where exceptions need to be detected, but not actually caught.
+class V8TryPropagate : public v8::TryCatch {

[yhirano, 2014/05/30 08:08:43]

How about classes https://codereview.chromium.org/304283004/ ?
I prefer them more because they are nestable.

+public:
+    ~V8TryPropagate()
+    {
+        // ReThrow() is a no-op if no exception has been caught, so always call.
+        v8::TryCatch::ReThrow();
+    }
+
+private:
+    v8::Handle<v8::Value> ReThrow();
+};
 
 } // namespace WebCore
 
 #endif // V8Binding_h