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

Source/bindings/modules/v8/custom/V8DeviceOrientationEventCustom.cpp

 /*
  * Copyright (C) 2010 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 copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 21 matching lines @@
 
 namespace blink {
 
 void V8DeviceOrientationEvent::initDeviceOrientationEventMethodCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     ExceptionState exceptionState(ExceptionState::ExecutionContext, "initDeviceOrientationEvent", "DeviceOrientationEvent", info.Holder(), info.GetIsolate());
     DeviceOrientationEvent* impl = V8DeviceOrientationEvent::toImpl(info.Holder());
     V8StringResource<> type(info[0]);
     if (!type.prepare())
         return;
-    bool bubbles = info[1]->BooleanValue();
-    bool cancelable = info[2]->BooleanValue();
+    v8::Local<v8::Context> context = info.GetIsolate()->GetCurrentContext();
+    bool bubbles;
+    V8_MAYBE(bubbles, info[1], BooleanValue(context), return);
+    bool cancelable;
+    V8_MAYBE(cancelable, info[2], BooleanValue(context), return);
     // If alpha, beta, gamma or absolute are null or undefined, mark them as not provided.
     // Otherwise, use the standard JavaScript conversion.
     bool alphaProvided = !isUndefinedOrNull(info[3]);
     double alpha = 0;
     if (alphaProvided) {
         alpha = toRestrictedDouble(info[3], exceptionState);
         if (exceptionState.throwIfNeeded())
             return;
     }
     bool betaProvided = !isUndefinedOrNull(info[4]);
@@ skipping 10 matching lines @@
         if (exceptionState.throwIfNeeded())
             return;
     }
     bool absoluteProvided = !isUndefinedOrNull(info[6]);
     bool absolute = info[6]->BooleanValue();
     DeviceOrientationData* orientation = DeviceOrientationData::create(alphaProvided, alpha, betaProvided, beta, gammaProvided, gamma, absoluteProvided, absolute);
     impl->initDeviceOrientationEvent(type, bubbles, cancelable, orientation);
 }
 
 } // namespace blink