Adjust texture priorities in preparation of impl-thread eviction of only some textures

cc/CCPrioritizedTexture.h

 // Copyright 2012 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 CCPrioritizedTexture_h
 #define CCPrioritizedTexture_h
 
 #include "CCPriorityCalculator.h"
 #include "CCResourceProvider.h"
 #include "CCTexture.h"
@@ skipping 90 matching lines @@
     void setManagerInternal(CCPrioritizedTextureManager* manager) { m_manager = manager; }
 
     Backing* backing() const { return m_backing; }
     void link(Backing*);
     void unlink();
 
     IntSize m_size;
     GC3Denum m_format;
     size_t m_bytes;
 
-    size_t m_priority;
+    int m_priority;
     bool m_isAbovePriorityCutoff;
     bool m_isSelfManaged;
 
     Backing* m_backing;
     CCPrioritizedTextureManager* m_manager;
 };
 
 } // namespace cc
 
 #endif