Add choke point for modifying non-AA rect draws (e.g., applying clipping)

src/gpu/batches/GrMSAAPathRenderer.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrMSAAPathRenderer.h"
 
 #include "GrAuditTrail.h"
@@ skipping 640 matching lines @@
                 }
             } else {
                 bounds = path.getBounds();
             }
             const SkMatrix& viewM = (reverse && viewMatrix.hasPerspective()) ? SkMatrix::I() :
                                                                                viewMatrix;
             SkAutoTUnref<GrDrawBatch> batch(
                     GrRectBatchFactory::CreateNonAAFill(paint.getColor(), viewM, bounds, nullptr,
                                                         &localMatrix));
 
+            SkASSERT(GrPipelineBuilder::kBoth_DrawFace == drawFace[p]);
             GrPipelineBuilder pipelineBuilder(paint, drawContext->mustUseHWAA(paint));
             pipelineBuilder.setDrawFace(drawFace[p]);
             if (passes[p]) {
                 pipelineBuilder.setUserStencil(passes[p]);
             } else {
                 pipelineBuilder.setUserStencil(userStencilSettings);
             }
 
             drawContext->drawBatch(pipelineBuilder, clip, batch);
         } else {
@@ skipping 54 matching lines @@
 
     GrPaint paint;
     paint.setXPFactory(GrDisableColorXPFactory::Make());
     paint.setAntiAlias(args.fIsAA);
 
     this->internalDrawPath(args.fDrawContext, paint, &GrUserStencilSettings::kUnused, *args.fClip,
                            *args.fViewMatrix, *args.fShape, true);
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////