Don't flush on read/write pixels unless necessary

include/gpu/GrSurface.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef GrSurface_DEFINED
 #define GrSurface_DEFINED
@@ skipping 117 matching lines @@
                              const void* buffer,
                              size_t rowBytes = 0,
                              uint32_t pixelOpsFlags = 0) = 0;
 
     /**
      * Write the contents of the surface to a PNG. Returns true if successful.
      * @param filename      Full path to desired file
      */
     bool savePixels(const char* filename);
 
+    bool hasPendingRead() const;
+    bool hasPendingWrite() const;
+    bool hasPendingIO() const;
+
 protected:
     GrSurface(GrGpu* gpu, bool isWrapped, const GrTextureDesc& desc)
     : INHERITED(gpu, isWrapped)
     , fDesc(desc) {
     }
 
     GrTextureDesc fDesc;
 
 private:
     typedef GrGpuResource INHERITED;
 };
 
 #endif // GrSurface_DEFINED