Add "sample locations" feature to GrProcessor

src/gpu/GrRenderTargetPriv.h

Index: src/gpu/GrRenderTargetPriv.h
diff --git a/src/gpu/GrRenderTargetPriv.h b/src/gpu/GrRenderTargetPriv.h
index f4931db1db7475feab36d24f163aeec8b4bc0f7e..c6c89336a99cd247618c6839c28ab899f278015d 100644
--- a/src/gpu/GrRenderTargetPriv.h
+++ b/src/gpu/GrRenderTargetPriv.h
@@ -9,6 +9,9 @@
 #define GrRenderTargetPriv_DEFINED
 
 #include "GrRenderTarget.h"
+#include "GrGpu.h"
+
+class GrStencilSettings;
 
 /** Class that adds methods to GrRenderTarget that are only intended for use internal to Skia.
     This class is purely a privileged window into GrRenderTarget. It should never have additional
@@ -27,6 +30,8 @@ public:
      */
     bool attachStencilAttachment(GrStencilAttachment* stencil);
 
+    const GrGpu::MultisampleSpecs& getMultisampleSpecs(const GrStencilSettings& stencil) const;
+
 private:
     explicit GrRenderTargetPriv(GrRenderTarget* renderTarget) : fRenderTarget(renderTarget) {}
     GrRenderTargetPriv(const GrRenderTargetPriv&) {} // unimpl