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

tools/clang/blink_gc_plugin/tests/class_requires_finalization_mixin.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_REQUIRES_FINALIZATION_MIXIN_H_
 #define CLASS_REQUIRES_FINALIZATION_MIXIN_H_
 
 #include "heap/stubs.h"
 
-namespace WebCore {
+namespace blink {
 
 class OffHeap : public RefCounted<OffHeap> { };
 class OnHeap : public GarbageCollected<OnHeap> { };
 
 class MixinFinalizable : public GarbageCollectedMixin {
 public:
     void trace(Visitor*);
 private:
     RefPtr<OffHeap> m_offHeap; // Requires finalization
     Member<OnHeap> m_onHeap;
@@ skipping 32 matching lines @@
     USING_GARBAGE_COLLECTED_MIXIN(NeedsNoFinalization);
 public:
     void trace(Visitor*);
 private:
     Member<OnHeap> m_obj;
 };
 
 }
 
 #endif