Fix caching of sample locations

src/gpu/GrRenderTargetPriv.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrRenderTargetPriv_DEFINED
 #define GrRenderTargetPriv_DEFINED
 
@@ skipping 15 matching lines @@
     /**
      * Attaches the GrStencilAttachment onto the render target. If stencil is a nullptr then the
      * currently attached GrStencilAttachment will be removed if one was previously attached. This
      * function returns false if there were any failure in attaching the GrStencilAttachment.
      */
     bool attachStencilAttachment(GrStencilAttachment* stencil);
 
     int numStencilBits() const;
 
     const GrGpu::MultisampleSpecs& getMultisampleSpecs(const GrStencilSettings& stencil) const;
+    uint8_t& accessMultisampleSpecsID() { return fRenderTarget->fMultisampleSpecsID; }
 
     GrRenderTarget::SampleConfig sampleConfig() const { return fRenderTarget->fSampleConfig; }
 
 private:
     explicit GrRenderTargetPriv(GrRenderTarget* renderTarget) : fRenderTarget(renderTarget) {}
     GrRenderTargetPriv(const GrRenderTargetPriv&) {} // unimpl
     GrRenderTargetPriv& operator=(const GrRenderTargetPriv&); // unimpl
 
     // No taking addresses of this type.
     const GrRenderTargetPriv* operator&() const;
     GrRenderTargetPriv* operator&();
 
     GrRenderTarget* fRenderTarget;
 
     friend class GrRenderTarget; // to construct/copy this type.
 };
 
 inline GrRenderTargetPriv GrRenderTarget::renderTargetPriv() { return GrRenderTargetPriv(this); }
 
 inline const GrRenderTargetPriv GrRenderTarget::renderTargetPriv () const {
     return GrRenderTargetPriv(const_cast<GrRenderTarget*>(this));
 }
 
 #endif