Make GrIODB keep pending IO refs on all resources it records into its cmd stream.

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
 
@@ skipping 93 matching lines @@
         }
     }
 
 private:
     mutable int32_t fRefCnt;
     mutable int32_t fPendingReads;
     mutable int32_t fPendingWrites;
 
     // This class is used to manage conversion of refs to pending reads/writes.
     friend class GrGpuResourceRef;
+    template <typename T> friend class GrPendingIOResource;
 };
 
 /**
  * Base class for objects that can be kept in the GrResourceCache.
  */
 class GrGpuResource : public GrGpuRef {
 public:
     SK_DECLARE_INST_COUNT(GrGpuResource)
 
     /**
@@ skipping 114 matching lines @@
 
     GrResourceCacheEntry*   fCacheEntry;  // NULL if not in cache
     const uint32_t          fUniqueID;
 
     GrResourceKey           fScratchKey;
 
     typedef GrGpuRef INHERITED;
 };
 
 #endif