Add use-chromium-style-naming option to Blink GC plugin.

tools/clang/blink_gc_plugin/tests/legacy_naming/trace_after_dispatch.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "trace_after_dispatch.h"
 
 namespace blink {
 
 static B* toB(A* a) { return static_cast<B*>(a); }
 
@@ skipping 30 matching lines @@
     A::traceAfterDispatch(visitor);
 }
 
 void D::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_a);
     Abstract::traceAfterDispatch(visitor);
 }
 
 }