Dynamically create stencil buffer when needed.

src/gpu/effects/GrConfigConversionEffect.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrConfigConversionEffect.h"
 #include "GrContext.h"
 #include "GrInvariantOutput.h"
@@ skipping 163 matching lines @@
         for (int x = 0; x < 256; ++x) {
             uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
             color[3] = y;
             color[2] = SkTMin(x, y);
             color[1] = SkTMin(x, y);
             color[0] = SkTMin(x, y);
         }
     }
 
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag |
-                  kNoStencil_GrSurfaceFlag;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fWidth = 256;
     desc.fHeight = 256;
     desc.fConfig = kRGBA_8888_GrPixelConfig;
 
     SkAutoTUnref<GrTexture> readTex(context->createTexture(desc, true, NULL, 0));
     if (!readTex.get()) {
         return;
     }
     SkAutoTUnref<GrTexture> tempTex(context->createTexture(desc, true, NULL, 0));
     if (!tempTex.get()) {
@@ skipping 84 matching lines @@
             kNone_PMConversion != pmConversion) {
             // The PM conversions assume colors are 0..255
             return NULL;
         }
         return SkNEW_ARGS(GrConfigConversionEffect, (texture,
                                                      swapRedAndBlue,
                                                      pmConversion,
                                                      matrix));
     }
 }