bindings: Use Maybe APIs in V8ScriptRunner (part 1)

Source/bindings/core/v8/NPV8Object.cpp

 /*
  * Copyright (C) 2004, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2007, 2008, 2009 Google, Inc.  All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 537 matching lines @@
         // on the object into an array.
         const char enumeratorCode[] =
             "(function (obj) {"
             "  var props = [];"
             "  for (var prop in obj) {"
             "    props[props.length] = prop;"
             "  }"
             "  return props;"
             "});";
         v8::Handle<v8::String> source = v8AtomicString(isolate, enumeratorCode);
-        v8::Handle<v8::Value> result = V8ScriptRunner::compileAndRunInternalScript(source, isolate);
-        ASSERT(!result.IsEmpty());
+        v8::Local<v8::Value> result;
+        if (!V8ScriptRunner::compileAndRunInternalScript(source, isolate).ToLocal(&result))

[dcarney, 2015/03/13 08:15:45]

use macros to remove the if(!whatever) block in most places.  if you don't the
code will quickly become unreadable. we had the same problem in the v8 runtime

[bashi, 2015/03/17 02:01:36]

We discussed how we handle ToLocal failure, and we reached a consensus that we
don't use macros. https://codereview.chromium.org/970403003/

Macros can't improve readability these cases.

+            return false;
         ASSERT(result->IsFunction());
         v8::Handle<v8::Function> enumerator = v8::Handle<v8::Function>::Cast(result);
         v8::Handle<v8::Value> argv[] = { obj };
         v8::Local<v8::Value> propsObj = V8ScriptRunner::callInternalFunction(enumerator, v8::Handle<v8::Object>::Cast(result), WTF_ARRAY_LENGTH(argv), argv, isolate);
         if (propsObj.IsEmpty())
             return false;
 
         // Convert the results into an array of NPIdentifiers.
         v8::Handle<v8::Array> props = v8::Handle<v8::Array>::Cast(propsObj);
         *count = props->Length();
@@ skipping 45 matching lines @@
 
         convertV8ObjectToNPVariant(isolate, resultObject, npObject, result);
         return true;
     }
 
     if (NP_CLASS_STRUCT_VERSION_HAS_CTOR(npObject->_class) && npObject->_class->construct)
         return npObject->_class->construct(npObject, arguments, argumentCount, result);
 
     return false;
 }