Check for xfer barriers in GrBatch, auto-issue barriers in GrGpu

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index cc3a92ac3e158476182ba96ce7f425538b2d28ba..69a4ec9ee8111750f8e506537200eeb0f9e91ee9 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -299,9 +299,6 @@ public:
                              const SkIRect& srcRect,
                              const SkIPoint& dstPoint) = 0;
 
-    // Called before certain draws in order to guarantee coherent results from dst reads.
-    virtual void xferBarrier(GrRenderTarget*, GrXferBarrierType) = 0;
-
     struct DrawArgs {
         DrawArgs(const GrPrimitiveProcessor* primProc,
                  const GrPipeline* pipeline,
@@ -432,6 +429,9 @@ private:
     // assumed 3D context state and dirty any state cache.
     virtual void onResetContext(uint32_t resetBits) = 0;
 
+    // Called before certain draws in order to guarantee coherent results from dst reads.
+    virtual void xferBarrier(GrRenderTarget*, GrXferBarrierType) = 0;
+
     // overridden by backend-specific derived class to create objects.
     // Texture size and sample size will have already been validated in base class before
     // onCreateTexture/CompressedTexture are called.