Don't reuse scratch textures patch

include/gpu/GrResource.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrResource_DEFINED
 #define GrResource_DEFINED
 
@@ skipping 48 matching lines @@
      * for this to return NULL. When resources have been release()ed or
      * abandon()ed they no longer have an owning context. Destroying a
      * GrContext automatically releases all its resources.
      */
     const GrContext* getContext() const;
     GrContext* getContext();
 
     void setCacheEntry(GrResourceEntry* cacheEntry) { fCacheEntry = cacheEntry; }
     GrResourceEntry* getCacheEntry() { return fCacheEntry; }
 
-    void incDeferredRefCount() const { SkASSERT(fDeferredRefCount >= 0); ++fDeferredRefCount; }
-    void decDeferredRefCount() const { SkASSERT(fDeferredRefCount > 0); --fDeferredRefCount; }
+    void incDeferredRefCount() const { 
+        SkASSERT(fDeferredRefCount >= 0); 
+        ++fDeferredRefCount; 
+    }
+
+    void decDeferredRefCount() const { 
+        SkASSERT(fDeferredRefCount > 0); 
+        --fDeferredRefCount; 
+        if (0 == fDeferredRefCount && this->needsDeferredUnref()) {
+            SkASSERT(this->getRefCnt() > 1);
+            this->unref();
+        }
+    }
+
     int getDeferredRefCount() const { return fDeferredRefCount; }
 
+    void setNeedsDeferredUnref() { fFlags |= kDeferredUnref_FlagBit; }
+
 protected:
     /**
      * isWrapped indicates we have wrapped a client-created backend resource in a GrResource. If it
      * is true then the client is responsible for the lifetime of the underlying backend resource.
      * Otherwise, our onRelease() should free the resource.
      */
     GrResource(GrGpu* gpu, bool isWrapped);
     virtual ~GrResource();
 
     GrGpu* getGpu() const { return fGpu; }
 
     // Derived classes should always call their parent class' onRelease
     // and onAbandon methods in their overrides.
     virtual void onRelease() {};
     virtual void onAbandon() {};
 
     bool isInCache() const { return NULL != fCacheEntry; }
-    bool isWrapped() const { return kWrapped_Flag & fFlags; }
+    bool isWrapped() const { return kWrapped_FlagBit & fFlags; }
+    bool needsDeferredUnref() const { return SkToBool(kDeferredUnref_FlagBit & fFlags); }
 
 private:
 #ifdef SK_DEBUG
     friend class GrGpu; // for assert in GrGpu to access getGpu
 #endif
 
     // We're in an internal doubly linked list
     SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrResource);
 
     GrGpu*              fGpu;               // not reffed. The GrGpu can be deleted while there
                                             // are still live GrResources. It will call
                                             // release() on all such resources in its
                                             // destructor.
     GrResourceEntry*    fCacheEntry;        // NULL if not in cache
     mutable int         fDeferredRefCount;  // How many references in deferred drawing buffers.
 
     enum Flags {
-        kWrapped_Flag = 0x1,
+        /**
+         * This resource wraps a GPU resource given to us by the user.
+         * Lifetime management is left up to the user (i.e., we will not 
+         * free it).
+         */
+        kWrapped_FlagBit         = 0x1,
+
+        /**
+         * This texture should be de-refed when the deferred ref count goes
+         * to zero. A resource gets into this state when the resource cache
+         * is holding a ref-of-obligation (i.e., someone needs to own it but
+         * no one else wants to) but doesn't really want to keep it around.
+         */
+        kDeferredUnref_FlagBit  = 0x2,
     };
     uint32_t         fFlags;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif