skia: Add support for CHROMIUM_image backed textures.

include/gpu/GrGpuResource.h

Index: include/gpu/GrGpuResource.h
diff --git a/include/gpu/GrGpuResource.h b/include/gpu/GrGpuResource.h
index 8103959984b14ccf5a7fde91783b5a8120eda178..5be586e41323297acb55315c9ff1e567f00d8d3d 100644
--- a/include/gpu/GrGpuResource.h
+++ b/include/gpu/GrGpuResource.h
@@ -260,6 +260,11 @@ public:
      **/
     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).