Make SkGpuDevice know its alpha type

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 119 matching lines @@
     typedef void* ReleaseCtx;
     typedef void (*ReleaseProc)(ReleaseCtx);
     
     void setRelease(ReleaseProc proc, ReleaseCtx ctx) {
         fReleaseProc = proc;
         fReleaseCtx = ctx;
     }
 
 protected:
     // Methods made available via GrSurfacePriv
-    SkImageInfo info() const;
+    SkImageInfo info(SkAlphaType) const;
     bool savePixels(const char* filename);
     bool hasPendingRead() const;
     bool hasPendingWrite() const;
     bool hasPendingIO() const;
 
     // Provides access to methods that should be public within Skia code.
     friend class GrSurfacePriv;
 
     GrSurface(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc)
         : INHERITED(gpu, lifeCycle)
@@ skipping 20 matching lines @@
         }
     }
     
     ReleaseProc fReleaseProc;
     ReleaseCtx  fReleaseCtx;
 
     typedef GrGpuResource INHERITED;
 };
 
 #endif