bindings: Add a macro for V8 Maybe<T> APIs.

Source/bindings/modules/v8/custom/V8CustomSQLStatementErrorCallback.cpp

 /*
  * Copyright (c) 2009, 2012 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 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "bindings/core/v8/ScriptController.h"
+#include "bindings/core/v8/V8Binding.h"
 #include "bindings/modules/v8/V8SQLError.h"
 #include "bindings/modules/v8/V8SQLStatementErrorCallback.h"
 #include "bindings/modules/v8/V8SQLTransaction.h"
 #include "core/dom/ExecutionContext.h"
 #include "wtf/Assertions.h"
 
 namespace blink {
 
 bool V8SQLStatementErrorCallback::handleEvent(SQLTransaction* transaction, SQLError* error)
 {
@@ skipping 25 matching lines @@
     exceptionCatcher.SetVerbose(true);
 
     v8::Local<v8::Value> result = ScriptController::callFunction(executionContext(), m_callback.newLocal(isolate), m_scriptState->context()->Global(), WTF_ARRAY_LENGTH(argv), argv, isolate);
 
     // FIXME: This comment doesn't make much sense given what the code is actually doing.
     //
     // Step 6: If the error callback returns false, then move on to the next
     // statement, if any, or onto the next overall step otherwise. Otherwise,
     // the error callback did not return false, or there was no error callback.
     // Jump to the last step in the overall steps.
-    return exceptionCatcher.HasCaught() || (!result.IsEmpty() && result->BooleanValue());
+    if (exceptionCatcher.HasCaught())
+        return true;
+    bool value;
+    V8_CALL(value, result, BooleanValue(isolate->GetCurrentContext()), return true);
+    return value;
 }
 
 } // namespace blink