skia: Add support for CHROMIUM_image backed textures.

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 242 matching lines @@
      */
     void abandon();
 
     /**
      * Dumps memory usage information for this GrGpuResource to traceMemoryDump.
      * Typically, subclasses should not need to override this, and should only
      * need to override setMemoryBacking.
      **/
     virtual void dumpMemoryStatistics(SkTraceMemoryDump* traceMemoryDump) const;
 
+    /**
+     * Whether the resource is reuseable by the resource cache.
+     */
+    virtual bool reuseable() const;
+
 protected:
     // This must be called by every GrGpuObject. It should be called once the object is fully
     // initialized (i.e. not in a base class constructor).
     void registerWithCache();
 
     GrGpuResource(GrGpu*, LifeCycle);
     virtual ~GrGpuResource();
 
     GrGpu* getGpu() const { return fGpu; }
 
@@ skipping 71 matching lines @@
     LifeCycle                   fLifeCycle;
     const uint32_t              fUniqueID;
 
     SkAutoTUnref<const SkData>  fData;
 
     typedef GrIORef<GrGpuResource> INHERITED;
     friend class GrIORef<GrGpuResource>; // to access notifyAllCntsAreZero and notifyRefCntIsZero.
 };
 
 #endif