Fix more inspector compile errors from merge as well as a ScriptState compile error.

Source/bindings/core/dart/DartScriptState.cpp

 /*
  * Copyright (C) 2013 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 71 matching lines @@
 
 PassRefPtr<AbstractScriptPromise> DartScriptState::createPromiseRejectedWithTypeError(const String& message)
 {
     RELEASE_ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 PassOwnPtr<AbstractScriptPromiseResolver> DartScriptState::createPromiseResolver(ScriptPromiseResolver*)
 {
     RELEASE_ASSERT_NOT_REACHED();
-    return nullptr;
 }
 
 class DartScriptStateProtectingContext : public AbstractScriptStateProtectingContext {
 public:
     DartScriptStateProtectingContext(DartScriptState* scriptState)
         : m_scriptState(scriptState)
     {
     }
 
     DartScriptState* get() const { return m_scriptState.get(); }
@@ skipping 22 matching lines @@
 
 #ifndef NDEBUG
 void DartScriptState::assertPrimaryKeyValidOrInjectable(PassRefPtr<SharedBuffer> buffer, const Vector<blink::WebBlobInfo>* blobInfo, IDBKey* key, const IDBKeyPath& keyPath)
 {
     // FIXMEDART: Implement without Dart<->V8 conversion.
     return v8ScriptState()->assertPrimaryKeyValidOrInjectable(buffer, blobInfo, key, keyPath);
 }
 #endif
 
 } // namespace blink