Add GrResourceCache2.

include/gpu/GrGpuResource.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGpuResource_DEFINED
 #define GrGpuResource_DEFINED
 
 #include "SkInstCnt.h"
 #include "SkTInternalLList.h"
 
 class GrResourceCacheEntry;
+class GrResourceCache2;
 class GrGpu;
 class GrContext;
 
 /**
  * Base class for objects that can be kept in the GrResourceCache.
  */
 class GrGpuResource : public SkNoncopyable {
 public:
     SK_DECLARE_INST_COUNT_ROOT(GrGpuResource)
 
@@ skipping 86 matching lines @@
      */
     void didChangeGpuMemorySize() const;
 
 private:
 #ifdef SK_DEBUG
     friend class GrGpu; // for assert in GrGpu to access getGpu
 #endif
 
     static uint32_t CreateUniqueID();
 
-    // We're in an internal doubly linked list
+    // We're in an internal doubly linked list owned by GrResourceCache2
     SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrGpuResource);
 
-    GrGpu*              fGpu;               // not reffed. The GrGpu can be deleted while there
-                                            // are still live GrGpuResources. It will call
-                                            // release() on all such objects in its destructor.
+    // This is not ref'ed but abandon() or release() will be called before the GrGpu object
+    // is destroyed. Those calls set will this to NULL.
+    GrGpu* fGpu;
+
     enum Flags {
         /**
          * This object wraps a GPU object given to us by the user.
          * Lifetime management is left up to the user (i.e., we will not
          * free it).
          */
         kWrapped_FlagBit         = 0x1,
     };
 
     uint32_t                fFlags;
 
     mutable int32_t         fRefCnt;
     GrResourceCacheEntry*   fCacheEntry;  // NULL if not in cache
     const uint32_t          fUniqueID;
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif