Mark DOMStringList.contains() as deprecated, add console warning.

Source/bindings/modules/v8/V8BindingForModules.cpp

 /*
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 51 matching lines @@
 static v8::Local<v8::Value> deserializeIDBValueArray(v8::Isolate*, v8::Local<v8::Object> creationContext, const Vector<RefPtr<IDBValue>>*);
 
 v8::Local<v8::Value> toV8(const IDBKeyPath& value, v8::Local<v8::Object> creationContext, v8::Isolate* isolate)
 {
     switch (value.type()) {
     case IDBKeyPath::NullType:
         return v8::Null(isolate);
     case IDBKeyPath::StringType:
         return v8String(isolate, value.string());
     case IDBKeyPath::ArrayType:
-        RefPtrWillBeRawPtr<DOMStringList> keyPaths = DOMStringList::create();
+        RefPtrWillBeRawPtr<DOMStringList> keyPaths = DOMStringList::create(DOMStringList::IndexedDB);

[jsbell, 2015/06/12 20:35:38]

Side note: I'm rather surprised to see this here. This was never documented or
specified to be a DOMStringList and Gecko doesn't implement it that way either,
and we have no tests asserting that it is a DOMStringList. This should be a
plain (but possibly frozen?) array.

I'll spin up a separate CL to change it.

         for (Vector<String>::const_iterator it = value.array().begin(); it != value.array().end(); ++it)
             keyPaths->append(*it);
         return toV8(keyPaths.release(), creationContext, isolate);
     }
     ASSERT_NOT_REACHED();
     return v8::Undefined(isolate);
 }
 
 v8::Local<v8::Value> toV8(const IDBKey* key, v8::Local<v8::Object> creationContext, v8::Isolate* isolate)
 {
@@ skipping 448 matching lines @@
     ASSERT(!exceptionState.hadException());
     if (expectedKey && expectedKey->isEqual(value->primaryKey()))
         return;
 
     bool injected = injectV8KeyIntoV8Value(isolate, keyValue.v8Value(), scriptValue.v8Value(), value->keyPath());
     ASSERT_UNUSED(injected, injected);
 }
 #endif
 
 } // namespace blink