Rename GrStencilBuffer to GrStencilAttachment

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 82f4931d6c49f6e0cd45d09f67d7e5d03eb7a7d3..71bef0730101548d77e2918b52b39c5696f563da 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -21,7 +21,7 @@ class GrPathRenderer;
 class GrPathRendererChain;
 class GrPipeline;
 class GrPrimitiveProcessor;
-class GrStencilBuffer;
+class GrStencilAttachment;
 class GrVertexBufferAllocPool;
 
 class GrGpu : public SkRefCnt {
@@ -491,7 +491,7 @@ private:
     virtual bool createStencilBufferForRenderTarget(GrRenderTarget*, int width, int height) = 0;
 
     // attaches an existing SB to an existing RT.
-    virtual bool attachStencilBufferToRenderTarget(GrStencilBuffer*, GrRenderTarget*) = 0;
+    virtual bool attachStencilBufferToRenderTarget(GrStencilAttachment*, GrRenderTarget*) = 0;
 
     // clears target's entire stencil buffer to 0
     virtual void clearStencil(GrRenderTarget* target) = 0;