clang/blink_gc_plugin: Replace 'WebCore' with 'blink'

tools/clang/blink_gc_plugin/tests/class_multiple_trace_bases.h

 // 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.
 
 #ifndef CLASS_MULTIPLE_TRACE_BASES_H_
 #define CLASS_MULTIPLE_TRACE_BASES_H_
 
 #include "heap/stubs.h"
 
-namespace WebCore {
+namespace blink {
 
 class Base : public GarbageCollected<Base> {
 public:
     virtual void trace(Visitor*);
 };
 
 class Mixin : public GarbageCollectedMixin {
 public:
     void trace(Visitor*);
 };
 
 class Derived : public Base, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(HeapObject);
     // Requires trace method.
 };
 
 }
 
 #endif