Fix caching of sample locations

include/gpu/GrRenderTarget.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 GrRenderTarget_DEFINED
 #define GrRenderTarget_DEFINED
 
@@ skipping 145 matching lines @@
     void setLastDrawTarget(GrDrawTarget* dt);
     GrDrawTarget* getLastDrawTarget() { return fLastDrawTarget; }
 
     static SampleConfig ComputeSampleConfig(const GrCaps& caps, int sampleCnt);
 
 protected:
     GrRenderTarget(GrGpu* gpu, const GrSurfaceDesc& desc,
                    SampleConfig sampleConfig, GrStencilAttachment* stencil = nullptr)
         : INHERITED(gpu, desc)
         , fStencilAttachment(stencil)
+        , fMultisampleSpecsID(0)
         , fSampleConfig(sampleConfig)
         , fLastDrawTarget(nullptr) {
         fResolveRect.setLargestInverted();
     }
 
     ~GrRenderTarget() override;
 
     // override of GrResource
     void onAbandon() override;
     void onRelease() override;
 
 private:
     // Allows the backends to perform any additional work that is required for attaching a
     // GrStencilAttachment. When this is called, the GrStencilAttachment has already been put onto
     // the GrRenderTarget. This function must return false if any failures occur when completing the
     // stencil attachment.
     virtual bool completeStencilAttachment() = 0;
 
     friend class GrRenderTargetPriv;
 
     GrStencilAttachment*  fStencilAttachment;
+    uint8_t               fMultisampleSpecsID;
     SampleConfig          fSampleConfig;
 
     SkIRect               fResolveRect;
 
     // The last drawTarget that wrote to or is currently going to write to this renderTarget
     // The drawTarget can be closed (e.g., no draw context is currently bound
     // to this renderTarget).
     // This back-pointer is required so that we can add a dependancy between
     // the drawTarget used to create the current contents of this renderTarget
     // and the drawTarget of a destination renderTarget to which this one is being drawn.
     GrDrawTarget* fLastDrawTarget;
 
     typedef GrSurface INHERITED;
 };
 
 
 #endif