Fix a bunch of implicit casts detected by the Win64 compiler

src/factory.cc

 // Copyright 2012 the V8 project authors. 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 documentation and/or other materials provided
@@ skipping 707 matching lines @@
   p = &buffer[kBufferSize] - space;
 
   for (unsigned i = 0; i < ARRAY_SIZE(args); i++) {
     if (space > 0) {
       *p++ = ' ';
       space--;
       if (space > 0) {
         MaybeObject* maybe_arg = args->GetElement(i);
         Handle<String> arg_str(reinterpret_cast<String*>(maybe_arg));
         const char* arg = *arg_str->ToCString();
-        Vector<char> v2(p, space);
+        Vector<char> v2(p, static_cast<int>(space));
         OS::StrNCpy(v2, arg, space);
         space -= Min(space, strlen(arg));
         p = &buffer[kBufferSize] - space;
       }
     }
   }
   if (space > 0) {
     *p = '\0';
   } else {
     buffer[kBufferSize - 1] = '\0';
@@ skipping 770 matching lines @@
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return Handle<Object>(value
                         ? isolate()->heap()->true_value()
                         : isolate()->heap()->false_value());
 }
 
 
 } }  // namespace v8::internal